Barnaby Joyce believes former cabinet minister Christian Porter deserves another chance to serve on the frontbench after time in political purgatory.
The former attorney-general quit as a minister after revealing some of his legal fees from a defamation action against the ABC were paid by anonymous sources.
Mr Porter sued the national broadcaster over a story about a historical rape allegation he strenuously denies.
Mr Joyce described the use of mystery money for Mr Porter's defence in the now-settled defamation claim as "not a good day at the wicket".
The acting prime minister thinks Mr Porter should be given another chance at a leadership role after spending time on the backbench, which he labelled "the corridor of the nearly dead".
"My own recommendation is that he is an incredibly capable politician," he told reporters on Monday.
Mr Joyce, who spent three-and-a-half years on the backbench before returning to the Nationals leadership, expects Mr Porter to use his extra time wisely.
"If he does that effectively I believe he should be given another chance at some future time in a senior role."
He said nothing illegal had occurred.
Labor vowed to continue pursuing Mr Porter, demanding he fess up about the donors and return the money or quit his WA seat of Pearce.
But Mr Porter has vowed to contest the next election and ruled out quitting beforehand, which would trigger a by-election.
Opposition leader Anthony Albanese maintained there were unanswered questions.
"Who provided this money? Why was it provided? How was it provided?" he said on ABC radio.
"Is there any conflict of interest? Does anyone who provided money have contracts with the government?"
Mr Albanese added Mr Porter's resignation from the ministry did not alleviate disclosure obligations.
"There are real reasons why members of parliament have obligations to declare publicly any private interests that they receive," the Labor leader said.
Mr Porter was adamant he did not breach ministerial standards, but quit as industry minister to avoid being "a very unhelpful distraction" for the government.
He maintained he could not and should not disclose the source of the money contributed through what he described as a blind trust.
While serving as attorney-general he named himself after the ABC published a sexual assault allegation, from a woman who had died, against an unnamed cabinet minister.
Mr Porter took the public broadcaster to court and settled the case before trial.
He explained he resigned because he would not pressure the trust to provide more information about its contributors, beyond confirming no prohibited foreign entities were involved.
"Ultimately, I decided that if I have to make a choice between seeking to pressure the trust to break individuals' confidentiality in order to remain in cabinet, or alternatively forego my cabinet position, there is only one choice I could, in all conscience, make," he said in a statement.
Australian Associated Press