Allegations swirling around Justice Minister Judith Collins' involvement with milk company Oravida were kept on the boil when NZ First leader Winston Peters spoke to a meeting in Wanganui on Friday.
Claims have been made that the company, in which Ms Collins' husband is a director, got preferential treatment after the minister visited China last year.
Last week Mr Peters suggested a Chinese import clearance certificate for Oravida's fresh milk and posted on the company's website in late December was linked to Ms Collins' visit to China and dinner with a Chinese border control official a few weeks earlier.
Ms Collins has consistently maintained that Oravida's business was not discussed when she met the unnamed Chinese border control official at what she says was a "private" dinner.
A botulism scare last year stopped Kiwi dairy products at the Chinese border, but last week Mr Peters told his 150-strong Wanganui audience at the Central Baptist Church that he believed Oravida had received preferential treatment.
"Oravida is one of two New Zealand companies exporting milk to China. But while Oravida was trading, the other New Zealand company is still not allowed back.
"I believe Collins used her position to advantage one company, the one her husband's involved with."
Mr Peters said the Prime Minister could not allow Ms Collins "to get away with it".
"If she was acting for all the companies exporting to China, I could have forgiven her," he said.