National MP Pansy Wong is under renewed pressure after information was produced in Parliament on Wednesday contradicting what her husband told an investigation into his travel.
A report released last week into the couple's travel on Mrs Wong's parliamentary perks cleared them of any systematic abuse of the system.
Sammy Wong told investigator Hugh McPhail that a trip he made to China in June 2005 was to meet with relatives and search family roots.
But on Wednesday, Labour MP Pete Hodgson questioned Prime Minister John Key in Parliament about Mr Wong's travel to Fujian province.
Mr Hodgson has information from a website that talks about Mr Wong accompanying former prime minister Dame Jenny Shipley at the launch of a biotechnology company during the trip.
Mr Key replied he did not know anything about it and invited Labour MPs to send any information to the Auditor-General.
Mrs Wong, the MP for Botany, resigned as a Cabinet minister in November.
Listen to Checkpoint interview with Pete Hodgson