MPs were given a 1.4 per cent pay rise despite Prime Minister John Key urging the Remuneration Authority to freeze their salaries.

A spokesman for Mr Key has revealed the prime minister was consulted by the independent authority, which announced the pay rise yesterday.

"He argued there should be a nil increase for MPs, or if there was to be one it should be in the band of other public sector pay settlements," the spokesman said.

The authority partly followed Mr Key's advice - it said the pay rise was roughly the same as public service increases and less than the inflation rate since the last increase.

It was backdated to July and brings a backbench MP's salary to $134,800.

Those with specific responsibilities get more than that, cabinet ministers now earn $249,100 and the prime minister $400,500.

Trade Unions have criticised the increase, pointing out the average wage is $49,474.

The Public Service Association (PSA) said the State Services Commission never agreed to backdated pay increases.

"MPs once again risk being seen as hypocrites for receiving gains others don't receive," said PSA national secretary Richard Wagstaff.

- NZPA