ACT Party leader John Banks says he negotiated a discounted room rate at the Hyatt Hotel in Hong Kong himself.
In Parliament on Wednesday, Labour MP Trevor Mallard asked whether Mr Banks had raised with the Prime Minister's office that the internet millionaire had got the minister a discount at the Hyatt Hotel.
Mr Banks rejects that allegation and says he negotiated a cheaper deal and paid for the accommodation himself.
Mr Banks says he has provided a copy of his wife's credit card statement showing he paid for last year's trip to Hong Kong in full.
He says Mr Mallard's comments are outrageous and defamatory and challenges him to repeat them without the protection of Parliamentary privilege.
Mr Banks faces a police investigation over electoral declarations from his 2010 Auckland mayoral campaign.
At issue is whether he knew that donations, declared as anonymous, were from Mr Dotcom and Sky City.
