Mr Palmer was reminded he was "under oath" when he claimed not to have known in advance that 200 Queensland Nickel workers were going to be made redundant in January.

In an at times fiery two-hour stretch, the former politician alleged "corruption at its highest level" had led to Queensland Nickel being knocked back for a $25 million loan.

But he denied the money was needed because the company could not pay its debts as far back as September, which could have made it insolvent months before going into administration.

"It's just bullshit," he said, when pressed on the issue by barrister Tom Sullivan, QC, for the special purpose liquidators charged with recovering tens of millions of taxpayer dollars paid out as entitlements when QNI collapsed.

Mr Palmer again turned his radar on Prime Minister Malcolm Turnbull, claiming the big four banks had all rejected overtures from the Townsville refinery operator, backed by Mr Palmer, "on instructions of the Prime Minister".

Those rejections came in a quick-fire series of meetings in the middle of September last year, but Mr Palmer previously told the court he met with Mr Turnbull about QNI in October, after which he formed the view federal and state governments were "determined to put Queensland Nickel out of business".

"I realised from the tone of that meeting that he was up to no good," Mr Palmer said on Thursday.

Mr Palmer argued that $1.95 billion in assets from the joint venture controlling Queensland Nickel, QNI Resources and QNI Metals, should have been enough to lend against, especially when he offered a further $250 million in other assets.

"I took the view that if $1.95 billion wasn't going to do it and $250 million wasn't going to do it … politically these people were going to sink north Queensland no matter what we did," he said, when asked why he had not put his personal assets up.

The company eventually collapsed into voluntary administration in January and was sent into liquidation earlier this year, leaving almost 800 people out of work and debts of about $300 million.

The court returned to an expletive-laden email from Clive Palmer telling his nephew not to "cover his arse" or he would "f--- everything", which the court heard was prompted by a draft letter to Queensland Treasurer Curtis Pitt..

On Monday, Mr Palmer failed to answer any questions about what instructions he had given QNI sole director Clive Mensink not to email him again.

"I told you what to do. Do it," he wrote

"Do not send me anything to cover your arse or you f--- everything.

"Do not contact me by email again."

On Thursday, Mr Palmer was slightly more responsive, saying he may "have told him to wipe his arse" with the draft letter Mr Pitt, who he said was "no one of significance, really".

"I had a very poor opinion of the treasurer's morals and his integrity and I didn't want to have any further discussions with him at all," he said.

"I'd told Mensink to forget about the Queensland treasurer, because I'd been told by (former Labor deputy premier) Jim Elder that the Labor Party had decided to sink us regardless."

Mr Palmer claimed Mr Mensink may have been trying to "cover his arse" for a future government job and the email ban came because the future of workers was a "serious issue" and best discussed face to face.

He was questioned about a memo from QNI's former chief financial officer Daren Wolfe to a senior National Australia Bank employee, apparently making complaints about the company's treatment.

Mr Palmer did not admit to dictating the memo, but said he was "aware" of the material in it.

"Everyone said the NAB was baddies and we should put it on the record regardless of what Turnbull and (Queensland Premier Annastacia) Palaszczuk wanted to do to us," he said.

Mr Palmer also shed light on the origins of the controversial Terry Smith email account, which the court heard was originally known as "Clive Palmer", before it was changed in 2012.

The Palmer United Party founder said he wanted to impress his wife with a romantic dinner but needed to go "incognito" to avoid media turning up, so he booked under the name "Terry Smith".

Mr Palmer said they enjoyed a "nice entree, main course and desert" and the evening was "very successful".

The mining magnate was questioned extensively about the definitions of insolvent trading and the responsibilities of company directors to prevent it, which claimed he "didn't fully" understand.

The court heard Aurizon issued QNI with a formal notice of default on November 27, 2015, for more than $12 million in debt, after Mr Palmer earlier said the company had agreed to defer the debt.

Mr Palmer wrote off the request for payment, and another strongly worded letter and December 10 as "commercial negotiations", with Aurizon acting as "paper tigers".

Mr Palmer stood down as a director of the company after being elected to federal parliament but Mr Sullivan, acting for PPB Advisory, has been trying to determine whether he acted as a shadow director, which Mr Palmer has denied.

He has produced an old green notebook purporting to grant him wide-ranging authority to direct QNI under an agreement of the Joint Venture Owners Committee, made up of only himself and nephew Clive Mensink.

The pair clashed several times throughout the morning, with Mr Sullivan at one stage reminding the witness he was "under oath", when he claimed not to have known 200 workers were going to be made redundant from QNI on January 15.

After initially denying advance knowledge of redundancies, the court heard Mr Palmer received details in December of 250 workers to be sacked but denied he made the final decision that eventually put 200 employees out of work in January.

On another occasion Mr Sullivan said: "You've got a temper, don't you Mr Palmer?"

"Not like you, you've got a temper," Mr Palmer replied.

Mr Palmer has consistently denied allegations from Mr Sullivan that QNI had a "systemic cash flow problem" as far back as September, possibly leading it to insolvent trading, pointing often to a report from Ernst and Young he said must have signed the company off being able to continue as a going concern.

The court heard as part of that report, the overarching Queensland Nickel group, containing QNI itself, had made its own representation to EY that "each entity in the group would continue as a going concern".

Mr Palmer's legal team appeared in the High Court at 2.15pm to question whether Mr Palmer was allowed to be re-called to the examination at a later date, with a hearing tentatively listed for November.

On Thursday morning, Mr Mensink, who he said was still working for QNI despite being on a ship somewhere in northern Europe, threatened legal action against the company's liquidators, FTI Consulting.