The half-sister of a 15-year-old girl who disappeared from inner-western Sydney seven years ago says her family continues to feel anguish over her loss.
The NSW government on Tuesday announced a $500,000 reward for information on the disappearance of Katrina Bohnenkamp, who was reported missing by her carers in early November 2012.
She was last seen at a Strathfield home in late October 2012.
Half-sister Jaide Simpson on Tuesday told reporters it had been terrible not knowing Katrina's whereabouts.
"It's been horrible not having answers and not knowing what happened to her. I've got so many different theories," she said.
"Hopefully we can get some kind of clarity and the theories can be put to rest."
Ms Simpson said Katrina had been planning out her life at the time she went missing and was a "fun, hyperactive, busy and kind" person.
"She just wanted to have the best life," she said.
"She had goals and things she wanted to do. For her to just disappear, it just doesn't fit.
"I just want her home. She's got two nephews waiting to meet her. She's got a home to come back to."
NSW Police said the reward would be offered for information leading to the arrest and conviction of those responsible for Katrina's disappearance, or for information on Katrina's recovery.
Detective Inspector Christie Houldin said police had spent seven years looking for information on Katrina.
"We are constantly looking for those answers for Katrina's family and for the wider community who are worried about Katrina. We hold grave concerns for Katrina's safety," Det Insp Houldin told reporters.
There had been a number of unconfirmed sightings of Katrina since she was last seen in October 2012, Insp Houldin said.
"Between October 26 and November 2 there were a number of alleged sightings but these have not been confirmed by investigators," she said.
"The details of the confirmed sighting don't give any information on where she has gone or where she could be now."
Katrina's disappearance will be the subject of a NSW coronial inquest beginning on November 27.