Premier Colin Barnett has confirmed that seven from WA were among the 28 Australians killed in the Ukraine airline disaster.
The West Australian casualties include well known South Perth Yacht Club member Nick Norris, 68, and three of his grandchildren, Otis, 8, Evie, 10, and Mo, 12.
It is understood they were returning from a holiday in Amsterdam.
Albany couple Arjen and Yvonne Ryder were also on the flight.
The WA Catholic Education Office confirmed late today a female staff member from one its schools had been on MH17.
"The staff member was a valued member of her school community and she and her family are in our thoughts and prayers at this difficult time," a spokeswoman for the office said.
A Department of Agriculture and Food spokeswoman confirmed a male staff member was also on the flight.
The man was reportedly travelling with his wife.
Both spokeswomen said they would not release the names of the people out of respect for their families.
Fears are held for German national Fatima Dyczynski, who was travelling to Perth to begin an internship with IBM.
Her parents, who live in Mosman Park, arrived in Perth on an AirAsia flight from Kuala Lumpur late this afternoon said they had been unable to contact their daughter.
Earlier today, Mr Barnett said he was "deeply shocked and horrified" to be told about crash.
"At this stage reports do seem to indicate that the plane was shot down by terrorists and, if so, this is a truly unspeakable and incomprehensible act," he said.
"On behalf of all West Australians, I wish to express my deepest sympathy to the families of all the victims and, in particular, the West Australian families involved."
Mr Norris' son Brack Norris told ABC Radio he heard about the crash from one of his sisters.
“She called me at 5.30am ... and said that the plane that dad was on had been shot down,” he said.
“Quite shocking and disbelieving that we're actually in this situation.”
Mr Norris was a long-time member of South of Perth Yacht Club, which today provided information to media on behalf his wife Lindy.
"Nick and Lindy are well loved and respected members of the club who contributed selflessly as volunteers for yachting regattas and events," club general manager David Harries said.
"Nick crewed for Lindy on their support boat helping to lay course marks for sailing fleets at SoPYC. Nick was a member for 16 years.
“The members of SoPYC are shocked by this tragic, senseless loss of family members and club members. It will have a lasting impact on the club and members.”
In addition to the seven West Australians killed, it has been confirmed nine other passengers were from Queensland, nine from Victoria, one from NSW and one from ACT.
There is no confirmation where the remaining victim was from and authorities have warned the number of Australian casualties could rise.
Others who were permanent residents in Australia but travelling on foreign passports are believed to be among the dead.
Delegates headed for an international AIDS conference in Melbourne are also among those killed.
Foreign Minister Julie Bishop said Australian officials were seeking permission to access the crash site, which was in rebel held territory in eastern Ukraine.
Prime Minister Tony Abbott said there was “strong evidence” the plane was shot down.
“This is a terrible tragedy for them, their loved ones, their families,” Mr Abbott told ABC radio on Friday.
“If it does turn out that this aircraft was brought down by a surface to air missile there is no doubt this would be ... an unspeakable crime and the perpetrators should swiftly be brought to justice.”
The Department of Foreign Affairs and Trade (DFAT) has the primary responsibility for notifying the families of victims and Western Australia Police are now doing what they can to assist.
People who have been affected by this tragedy can call Department for Child Protection and Family Support on 1800 032 965 to access emotional and practical assistance. The phone line can put people in touch with specialised services to meet individual needs.
Australians killed on MH17
VICTORIA: RIZK, Albert, RIZK, Maree. Husband and wife from Sunbury north of Melbourne.
Albert and Maree Rizk are understood to have been returning to Australia on the flight, after a month-long holiday in Europe. Mr Rizk was a director of the local Raine and Horne real estate branch.
TEOH, Elaine, MAHLER, Emiel. Melbourne's Elaine Teoh and Emiel Mahler, both 27, were travelling to a wedding in Malaysia when the flight they were on travelled into Ukrainian airspace. Ms Teoh, originally from Penang in Malaysia, and Mr Mahler, a Dutch national, lived in Melbourne where they worked in the finance sector.
DAVISON, Frankie, DAVISON, Liam. The Toorak College (Mt Eliza) teacher and her husband were on board the flight. They left behind two children, Milly and Sam.
GUARD, Roger, GUARD, Jill. Toowoomba couple, doctors Roger and Jill Guard, were reportedly returning to Australia after holidaying following a medical conference. Roger Guard was director of pathology at Toowoomba Hospital, while Jill Guard worked as a GP. Both were well-regarded in the Toowoomba and Queensland Health communities.
SIDELIK, Heidi. The Gold Coast woman, aged in her late 50s was reportedly travelling home from a friend's wedding in Europe on flight MH17, according to the Gold Coast Bulletin. She moved to Burleigh from Melbourne four years ago. It's been reported she was originally from Adelaide. Also there are reports of a Sunshine Coast couple and four people from the Brisbane suburb of Indooroopilly.
WA: NORRIS, Nick. Nick Norris was on board with three of his grandchildren, the managing director of management consulting firm Collaborative Systemic Change Pty Ltd. Survived by daughter Kirstin, who is in the Navy and living in Sydney, and son Brack.
Arjen and Yvonne Ryder, a couple from Albany.
NSW: - One confirmed; two feared. TIERNAN,Philomene and Sister Philomene Tiernan, a nun who taught at Kincoppal at Rose Bay, was among those killed. Among those paying tribute were Communications Minister Malcolm Turnbull.
“Many women incl my wife Lucy & daughter Daisy were inspired by the love of Sr Phil Tiernan RSCJ” he tweeted.
CLANCY, Michael, CLANCY, Carol. Retired Wollongong couple Michael and Carol Clancy, believed to be in their 60s, are understood to have been on the flight following a three-week European holiday. The school where Mr Clancy taught, Albion Park, sent a letter home to parents.
ACT: DERDEN, Liliane. Mother of two Liliane Derden, 50, from Hall in Canberra's north. Ms Derden worked for the National Health and Medical Research Council, whose staff expressed deep sadness at the loss of a valued colleague and friend.
NT: Fears three NT residents have been killed. NT chief minister Adam Giles says it's believed a teacher from a remote community and a couple from Palmerston were on the flight.
Some of the victims may not be Australian passport holders.