Former Liberal MP Stuart Robert has denied allegations money was channelled to a company linked to him by a consulting business in order to win government contracts.
A parliamentary inquiry examining Mr Robert's links to consultancy firm Synergy 360 published evidence from the firm's co-founder Anthony Daly on Wednesday under parliamentary privilege.
The evidence alleges the consulting company set up a firm to send money to Mr Robert, in exchange for the former MP helping the firm win government contracts.
Mr Robert has hit back at the allegations, claiming they were a "by-election witch hunt" ahead of the upcoming poll in Fadden, which was triggered by his resignation.
He said he did not believe he had met Mr Daly or had spoken with him.
"I reject completely all of his allegations in the strongest possible terms, and I note that he had only made them under privilege where he is immune from legal consequence,'' Mr Robert said in a statement.
"I note he has provided zero evidence, simply made wild unsubstantiated allegations under privilege that are all completely and utterly wrong.
"This is an extraordinary abuse of privilege and extraordinary that a committee would release as such with zero evidence that is contrary to every bit of testimony they have heard to date and contrary to the Watt review that found zero misconduct in any contract dealing. Zero."
He said Mr Daly's submission to the inquiry was made with no evidence, describing the accusations as "wild".
"I reiterate what I have said numerous times. At no time have I ever been paid for any advice or guidance in any form," Mr Robert said.
"At no time did I lobby to assist any firm in such a manner."
Government Services Minister Bill Shorten said on Wednesday further investigations into the allegations were needed.
However, he didn't say if the matter would be referred to the new National Anti-Corruption Commission, which starts on Monday.
"Ultimately, it is up to the commissioner what they investigate. It is an independent body, free of government," Mr Shorten said.
Opposition Leader Peter Dutton said corruption allegations should be referred to the new federal agency.
"If there is evidence that people believe they have, it should be referred for independent investigation (and) we would support that process," he told reporters in Perth.
Mr Daly said in his statement he was willing to co-operate with the commission.
Voters in Mr Robert's former electorate of Fadden on the Gold Coast will head to the polls on July 15 to elect his replacement to parliament.
