Scott Morrison has sidestepped a question about whether he sought assurances from Clive Palmer that Queensland Nickel workers will be paid the $7m they are owed at the time the Liberal party entered a preference deal with the controversial businessman’s United Australia party.

Morrison’s deflection on the hustings in Perth came as Palmer resumed his criticisms of the ALP, suggesting Labor was saying one thing but doing another on preferences. In a prepared statement read out to journalists on Monday, Palmer referenced a series of conversations he claims he had with Labor figures about UAP preferences, and declared Bill Shorten’s “repeated lies about preferences confirm my judgment that he’s not morally fit to be prime minister of Australia”.

Campaigning ahead of Monday night’s first leader’s debate, Morrison was asked whether he sought assurances that Queensland Nickel workers would be paid not just the remaining $7m but also the $70m picked up by taxpayers before striking the recent preference deal with Palmer and the UAP.

Morrison didn’t answer the question he was asked, telling reporters: “[Palmer] put that money aside as I understand and the other matters are being pursued through the courts. Those matters are going through the court.”

The prime minister then advised Labor – which has been intensely critical of the UAP preference deal – to “take a chill pill on this discussion”.

Separately in Brisbane, Palmer appeared at a press conference and read a statement and then departed before taking any questions.

While Labor has been blasting the Liberals for days about dealing with Palmer given his parliamentary record and corporate controversies, Palmer on Monday detailed several contacts with Labor figures about UAP preferences, including the Queensland senator Anthony Chisholm, and a “former Labor minister” who he did not name.

“What bothers me about the Labor party is their willingness to lie repeatedly and that must to me be an indication of dishonesty,” Palmer said.

“Shorten only backtracked on his statements and admitted these lies when he was found out and realised he could not hide from people what had happened.”

Chisholm later issued a statement refuting Palmer’s version of events. He said his contacts with the businessman were an attempt “to do due diligence on what the Palmer party’s intentions were, as I have done in previous elections”.

“In recent weeks I had two very brief phone conversations in an attempt to discover what role Mr Palmer would play in the federal election. At no stage did I negotiate or offer Mr Palmer anything in regard to preferences. I was not authorised to offer anything and I didn’t.”

Palmer said on Monday his political party had decided to back the Liberals in this election because “no one can deny the fact Morrison has delivered a good economic numbers and a strong economy”.

“While we may have differences on how that strong economy is used, we cannot ignore that the Liberals’ economic management has been superior to the previous Labor governments of [Julia] Gillard and [Kevin] Rudd who destroyed the very fabric of our nation.”

Palmer, who is positioning himself as kingmaker in the campaign with a massive advertising spend that has increased his vote in Queensland, has attempted to defuse criticism of his corporate record by paying $7m into a trust fund for the remaining unpaid entitlements of Queensland Nickel workers, to be disbursed on 21 May, three days after the election.

The Australian Workers’ Union Queensland secretary, Steve Baker, has told Guardian Australia it is “unusual” for Palmer to promise to pay workers’ unpaid entitlements but then “delay until after the election”.

“And that makes me suspicious about payment being made,” he said.

Palmer on Monday said he had held discussions with Michael O’Connor of the CFMEU in the past couple of weeks about his failed nickel plant. He said he had told O’Connor the administrator “had sacked workers over our protest and offers to keep them employed and to pay all creditors in 2016”.

He said he had “decided personally to arrange for payment of any outstanding entitlements to all former workers of Queensland Nickel”.

“Considering the hard times being experienced in Townsville and although I was just a shareholder of the holding company of Queensland Nickel at the time, with no personal liability, I had arranged a payment of $7m for that purpose to be paid in a solicitor’s trust account so he could pay all the workers and deal with all the claims in accordance with Australian tax law”.

“That payment has been made and he’s currently dealing with the claims that have current been received. Mr O’Connor was very helpful and offered advice on how the union movement could assist in reopening the refinery”.

In addition to the corporate controversies, at least 19 UAP candidates have submitted incomplete or inconsistent information to the Australian Electoral Commission, failing to provide evidence they are eligible to run for parliament.

On Monday, Labor’s deputy leader, Tanya Plibersek, continued the ALP’s criticism of the Liberal deal with Palmer and the UAP: “What really worries me, Scott Morrison is so desperate he’s prepared to put his arm around Clive Palmer to do a deal, to try to cling desperately on to power.

“What is in it for Clive Palmer? What deal has Scott Morrison made? We know that Clive Palmer does nothing for people without expecting some return on his investment.”

Plibersek said that deal would lead to “cuts and more chaos, and it’s incredible that Scott Morrison should be prepared to inflict those cuts and chaos on Australians, just to cling desperately to power”.