Some of the state's highest paid workers will escape the WA government's $1,000 limit on pay rises until late 2019, with doctors set to enjoy increases almost six times that amount.

It raises questions about Premier Mark McGowan's claim the policy treats everyone in the public sector fairly, and highlights a difficulty for the government in reducing the costs of the $8.6 billion health sector.

Mr McGowan announced last week that his government was replacing its policy of restricting annual wages growth to 1.5 per cent with a maximum $1000 a year pay rise, or $19.20 a week.

"We think it's fair, we think it's reasonable, it helps those at the bottom the most but those who can most afford it don't get as big a pay rise as they might have expected," he said when announcing the policy.

"This will save the state $500 million over the course of the next four years."

While the policy was effective immediately, existing enterprise bargaining agreements (EBAs) will be honoured.

Under the EBA negotiated with the Australian Medical Association (WA), the more than 5000 doctors working in the public hospital system will receive pay rises of more than $1000 until September 2019.

The most senior doctors stand to boost their pay by almost $6000 a year, as part of their annual 1.5 per cent increases.

AMA (WA) president Andrew Miller said they were supportive of the $1,000 policy, were working with the government to improve efficiencies in the health system, and would not make unreasonable wage claims when their EBA expired.

"We know that the economy's not great and royalties aren't flowing," he said.

"But we at the same time have to be fair and reasonable.

"We have to compete for difficult-to-find doctors with organisations around the world and in Australia."

But the policy does not benefit some of the state's lowest-paid nurses, who are locked in to pay rises of less than $1000 until their EBA, negotiated by the Australian Nursing Federation's WA branch, expires in October 2018.

Enrolled nurses working in mental health and Mothercraft nursing will see only an extra $783 to $932 in their pay packets, with the lowest-level registered nurse getting $970.

The ANF was contacted for comment.

What do medical professionals earn?

Doctors Salary October 2016 Salary October 2017 Salary October 2018 Intern $76,177 $77,319 $78,479 Senior consultant (Year 9) $377,672 $378,832 $384,515 Nurses Enrolled mental health nurse $55,665 $56,500 Enrolled nurse (Mothercraft) $52,213 $52,996

Not all workers disadvantaged

Other workers whose EBAs guarantee them pay rises of more than $1,000 include 10,500 education assistants and 4,500 miscellaneous workers, including cleaners, gardeners and childcare workers — all receiving a 2.5 per cent pay rise brokered by the powerful union United Voice.

Education assistants are scheduled to receive a 2.5 per cent pay rise on January 1, meaning the lowest paid will get the equivalent of a $22.80 a week, or $1,190 a year, boost.

Even the lowest paid cleaner's pay will increase by $22.70 a week, equating to $1,185 a year, while a senior child care worker will get an extra $28.40, equivalent to $1,482.

The government has not set a time limit on the expiry of the $1,000 policy, but has indicated it could last its entire four-year term.

It will apply to the new EBAs being negotiated by the public sector, police and teacher unions, which represent a significant number of state government employees.

The acting president of the WA Police Union, Brandon Shortland, said he was frustrated and disappointed the new policy had been introduced into their EBA discussions, with most of their workers worse off as a result.