The Labour Party is accusing State Services Minister Tony Ryall of breaching the State Sector Act by interfering in polytechnic pay negotiations.
Mr Ryall met board chairs and the management of three polytechs last week.
Labour's state services spokesperson, Grant Robertson, says the minister delivered a dressing down about current and recent pay negotiations.
He says pay talks are a matter for chief executives under the State Sector Act and Mr Ryall should "butt out".
Mr Robertson says the minister is concerned about agreements with a 2% or 3% pay rise, and if the Government wanted a pay freeze, it should have said so openly.
Mr Ryall says he had "appropriate discussions" with the polytechs.