Independent MP Chris Carter is to be fined by the Speaker of the House for being absent from Parliament without leave.
Mr Carter, who was kicked out of the Labour Party this week, has been absent from the House for question time and debates on legislation, since his return from sick leave.
He was spotted at a gym by Radio New Zealand on Thursday.
Mr Carter says he was working out of his Te Atatu electorate office.
MPs are required to be present in the Parliamentary precinct while the House is sitting, or face a $10 fine.
The Speaker says he can't certify that Mr Carter's absence this week is due to illness or was otherwise unavoidable, and deductions will be made.