Clive Palmer says he has formally launched legal proceedings against Prime Minister Malcolm Turnbull, through which people will find out "what really happened" in the collapse of Queensland Nickel.

"Malcolm Turnbull will have his day in court to tell the Australian people what really happened about Queensland Nickel and Senator (Michaelia) Cash will get her time in court too to make her explanation," the former MP said as he arrived at Federal Court in Brisbane on Wednesday.

After briefly speaking to reporters Mr Palmer said he would give further details at a news conference later in the morning.

"We will see what really happened up there and what a tragedy it was for the people of North Queensland," he said.

"I've got to go in, I can't say much more."

On Tuesday, Mr Palmer said he will launch a $10 million defamation lawsuit against Mr Turnbull, who it is claimed allegedly besmirched the businessman's name over the Queensland Nickel collapse.

The former federal MP also says he will sue Employment Minister Michaelia Cash for $250,000 for saying responsibility for the nickel refinerry business lay with him.

Mr Palmer's lawyer Sam Iskander wrote to Senator Cash's office in October last year, claiming the businessman was being shunned and excluded by friends, employees and professional colleagues as a result of her comments and feared reprisals against himself and his family.

Mr Iskander said he would start legal action in the Brisbane District Court within 28 days unless Senator Cash issued a public apology and agreed to pay $150,000 in damages.

Mr Palmer was at the court to face a grilling about the collapse but said he would be out by about 11am and would address the media.

"It's very pleasing what's happened with the investigation so far," he said.

"The truth's coming out."

Queensland Nickel collapsed in early 2016 with debts of about $300 million, leaving close to 800 people out of work.