Clive Palmer's wife has told the Federal Court in Brisbane that she approved the transfer of about $180 million to a Bulgarian company controlled by her husband, but doesn't know what happened to it.

Key points: Anna Palmer gave evidence about her role as a former director of Mineralogy

Anna Palmer gave evidence about her role as a former director of Mineralogy The Federal Court heard she approved the transfer of 130 million Swiss francs to a Bulgarian company controlled by Clive Palmer

The Federal Court heard she approved the transfer of 130 million Swiss francs to a Bulgarian company controlled by Clive Palmer Ms Palmer told the court the transfer was about "diversifying assets", not "disposing" of the money

Anna Palmer was questioned at a public examination by liquidators investigating the collapse of Mr Palmer's Queensland Nickel refinery in Yabulu, north of Townsville.

She told the court that in 2018, while she was director of her husband's flagship company Mineralogy, she approved a transfer of 130 million Swiss francs ($A180 million) to a Bulgarian company called Palmer Investments.

The court heard that under the agreement, Mineralogy had to then pay interest on the money, which wasn't repayable by the Bulgarian company for 50 years.

Barrister John Peden — acting on behalf of liquidators — questioned how the loan could possibly be of benefit to Mineralogy.

"Wouldn't it just have been better to stash it under the mattress?" he asked.

"No," Mrs Palmer replied.

Mrs Palmer said it was an investment that was about "diversifying assets" and rejected a suggestion she was "disposing" of the money.

Control of Mineralogy was handed back to Clive Palmer in February after his wife was sole director for several months. ( ABC News: Ellie Sibson )

"Have you asked your husband [what happened to the 130 million Swiss francs?]" Mr Peden asked.

"I don't remember," she replied.

The court heard Ms Palmer was the sole director of Mineralogy between October last year and February, when she was removed and control was handed back to her husband.

During another hearing earlier this month, she told the court Mr Palmer was being funny when he told liquidators she was in control of managing the finances.

A wider lawsuit against Mr Palmer, his nephew Clive Mensink and associates over the collapse of Queensland Nickel is scheduled to go to trial in the Supreme Court in Brisbane in July.