Primary school teachers are set to make a collective decision on the Government's pay offer today

NZEI members are being offered up to a 4.7-percent increase within 12 months for those at the top of their pay band.

The rest would receive annual pay increases above inflation.

Teachers are voting through to 5pm tonight - if they reject the offer, they will then vote on strike action.

Public Service Commissioner Sir Brian Roche says there's no room to move on the offer - which would cost taxpayers an extra 450-million dollars over four years.