Embattled Labor MP Anthony Byrne has quit as deputy chair of federal parliament's powerful intelligence and security committee.
Mr Byrne earlier in the week admitted he paid for other people's ALP memberships during an Independent Broad-based Anti-corruption Commission inquiry into branch stacking.
The Victorian MP resigned from the Parliamentary Joint Committee on Intelligence and Security, which he deputy chaired, on Thursday.
"The work of the PJCIS is crucial to Australia's national security and its integrity should never be questioned," Mr Byrne said in a statement.
"I have always put the work of this bipartisan committee first and have always served in its best interests."
He said he would continue to fully co-operate with the IBAC inquiry and not make further comment while proceedings continued.
Left faction senator Jenny McAllister has been nominated to replace Mr Byrne as the PJCIS deputy chair.
Melbourne-based backbencher Peter Khalil, who was a national security adviser to former prime minister Kevin Rudd, will join the committee.
"These two members of parliament will continue Labor's tradition of strongly supporting the work of this committee and the role it plays in our democracy," Opposition Leader Anthony Albanese said.
He thanked Mr Byrne for making important contributions to the committee in Australia's national interest.
Committee chair and Liberal senator James Paterson said he understood Mr Byrne's decision to quit after his IBAC admissions.
"He has given very good service to the PJCIS and Australia's national security on and off over the last 15 years," Senator Paterson told Sky News.
"I've always found him very driven by Australia's national security and able to work with the government in a very constructive and bipartisan way."
He said he had no concerns about Mr Byrne's "first-rate" contribution to the committee.
Mr Albanese is resisting calls to expel Mr Byrne, who broke Labor Party rules by engaging in branch stacking, which is not illegal.
"We'll wait while the hearings are going on," the Labor leader told 2GB radio.
"Halfway through people's testimonies, you don't reach a verdict.
"We will deal with the issues when we have all of the information."
Australian Associated Press