The Liberal chairman of a federal parliamentary economics committee has angrily rejected accusations he shared the personal information of voters with a private company.
Tim Wilson has rubbished the "fictitious" claims after being accused of politicising taxpayer-funded public hearings into a contentious Labor tax policy.
"This is just complete rubbish," he told Sky News on Monday.
"This is just a grubby, pathetic, sad smear campaign."
Labor has referred Mr Wilson to the Australian Federal Police over claims personal data gathered by the parliamentary inquiry was given to a fund manager.
Mr Wilson acknowledged his official website, which encouraged people to give evidence to the inquiry, also included a petition from Wilson Asset Management.
He holds shares with the fund manager and is a distant cousin of its owner.
Some people who signed up to give evidence at the public hearings through the MP's website have since received advertising material from the fund.
Mr Wilson said his shares would not be impacted by Labor's franking credits policy and argued Geoff Wilson was merely a distant relative.
"You have to go back to the 1850s to draw this ridiculous connection," he said.
Mr Wilson has led town hall-style meetings across the country into Labor's plans to scrap franking credits, a cash refund utilised by self-funded retirees.
"My electorate is the third most impacted in the country - I am going to stand up for them," Mr Wilson said.
"I am going to fight for them no matter what mud or smear Labor throws at me."
The parliamentary inquiry is unusual in that it is investigating an opposition policy and has not scheduled formal witnesses, having instead opted to give members of the public three minutes each to speak.
Shadow treasurer Chris Bowen has renewed calls for Mr Wilson to resign, saying the hearings are an "arrogant, juvenile, undergraduate" approach to politics.
"This guy just doesn't get it. If he doesn't resign, the prime minister should sack him," he told reporters in Canberra.
"Every time he opens his mouth he increases the case for his own resignation."
Mr Bowen says the Liberal MP should disclose who else helped fund his official website, aside from his distant relative.
"The Australian people are entitled to know who paid for the website," he said.
"Where was the money coming from?"