More WA doctors are refusing to endorse parents who object to their children being vaccinated but who need a letter from their GP to get government benefit payments.
It comes as new Federal Human Services Department figures reveal an extra 479 WA children were added to the conscientious objectors' database last year - a 13 per cent increase on the previous year.
It gives WA one of the highest rates in the country.
It means 4300 WA children - almost 2 per cent of those aged under seven - are listed on the Australian Childhood Immunisation Register as unimmunised on philosophical or moral grounds, a rise which has alarmed local doctors.
Australian Medical Association WA president and Port Kennedy GP Richard Choong said he refused to sign conscientious objection forms, and other doctors did likewise.
Since July 2012, families have been required to have their children fully immunised or lodge a conscientious objection in order to get the family tax benefit supplement.
Dr Choong said it was up to doctors to decide for themselves, but they were not obliged to complete the form.
He also supported a move to refer to conscientious objectors as "vaccine refusers".
"These figures don't surprise me because as well as having one of the highest rates of conscientious objectors, WA is one of the lowest immunised States in Australia," he said.
"Some of the adverse reactions to the flu vaccine that happened to WA kids are still damaging because people tend to lump all vaccinations together, so it's all-or-nothing.
"But it's very disappointing because a lot of their decision is based on misinformation and hearsay, and we know bad things happen when vaccination rates slip."
Dr Choong said the recent cases of measles in WA were a timely reminder of the risks posed by unimmunised children to themselves and others.
WA immunisation strategy implementation steering committee chairwoman Rosanna Capolingua said unimmunised children lowered herd immunity, so even children whose parents wanted them protected and immunised were at risk if they were too young to have completed their vaccination schedule.
"When you're a conscientious objector, you're making a decision for your own kid but you're also making a decision for the community," she said.
"Many have been frightened by propaganda about the risks and we have a lot of work to do to take that fear away and reassure them vaccination is part of a healthy childhood and has saved thousands of lives."
Dr Capolingua said a recent measure to try to improve immunisation rates was having a clinic at Princess Margaret Hospital to create an opportunity to have visiting children vaccinated.
Other moves under way included following up school records on immunisation more closely and giving GPs better access to patient information on the national immunisation register.
When she was a child, Deanne Brescacin and her three elder sisters were vaccinated without a second thought, so she adopted the same "no-brainer" approach when she had children.
The Perth mother of two said she did not blindly accept claims about the benefits, but the weight of evidence was compelling compared with the unscientific claims from the anti-vaccination lobby.
She said knowing Archie, 5, and Otis, 2, were fully vaccinated gave her peace of mind as a parent. "I felt I needed to do it for my kids," she said.
With a background in health promotion, her support for childhood immunisation spurred her interest in the Immunisation Alliance WA, a community-based support group where she works as a project officer.
The group is launching a campaign "I Immunise" this week to encourage parents in alternative sections of the community to vaccinate their children.
Many have been frightened by propaganda about the risks and we have a lot of work to do. " Immunisation advocate Rosanna Capolingua