Labour Party leader Andrew Little is calling for the Foreign Affairs Minister to step down for what he calls misleading Cabinet over dealings with a Saudi businessman.
In Parliament, Labour has described a payment of more than $11 million of taxpayers' money, to help set up Hamood Al-Ali Al-Khalaf's farm, as bribery.
Murray McCully said the businessman claimed he had been misled by former Labour ministers about live sheep exports and wanted to sue for $30 million.
But Mr Little said Mr McCully had no place in Cabinet.
"He has dressed up a $4 million facilitation payment, which in many other countries is a bribe, as something other than what it is, relating to IP - a settlement of a legal claim. It has nothing to do with that," he said.
"In my view, from what I've seen, the Cabinet paper I've seen, he has misled Cabinet."
Mr Little said Prime Minister John Key needed to set a standard and remove Mr McCully from Cabinet.
Mr McCully has been travelling overseas and has been unavailable for comment.
Mr Key said ministers in the former Labour Government had misled Mr al-Khalaf about investing in the country and the businessman had threatened to sue for $30 million.
When asked if the potential legal action was also related to National indicating it would lift the live sheep export ban in 2009, Mr Key said he did not know the details.
"Don't know the details of that. All I know was that there was the potential threat of a lawsuit - that was one issue but there were quite a wide variety of issues."