ACT MP David Garrett says he does not believe he intimidated two submitters to Parliament's law and order select committee, as alleged by the Labour Party.
Labour Party MP Clayton Cosgrove believes Mr Garrett breached parliamentary privilege when he told two prison guards their submission would stop them from getting a job in a privately run prison.
He says Mr Garrett's behaviour was shameful, and brought the select committee process into disrepute.
Mr Cosgrove says the guards had experience working under private prison management and were providing expert opinions.
Corrections Minister Judith Collins has also weighed in, saying the comments were totally inappropriate.
But Mr Garrett says it was never his intention to intimidate, and he is looking forward to responding to Labour's complaint.
Speaker of the House Lockwood Smith will decide whether to refer the matter to Parliament's privileges committee.