"It seemed to be pretty much in line with the national average, maybe slightly lower than that, and so I've written back and said in principle we're comfortable with that."
Quarterly Employment Survey data shows average pay increased by almost 2.9 per cent in the year to June.
Assuming the MPs' pay increase is "slightly lower" at 2.5 per cent, a backbencher's basic pay would increase by $3525 to $144,525. Mr Key's pay would rise by $10,275 to $421,275.
Any increase is likely to be backdated to July which at 2.5 per cent would mean a pre-tax lump sum of $1762 for backbenchers.
Last year, just days before the election, Mr Key said the authority's decision to give MPs a $5000 lump sum to offset the loss of travel perks was unnecessary and he was disappointed the authority had awarded it.