Labour's foreign affairs spokesperson, David Shearer, says the Foreign Minister Murray McCully knew more about the Malaysian diplomat case than he has admitted.
After being charged with burglary and sexual assault, Muhammad Rizalman was allowed to claim diplomatic immunity and leave the country.
Mr Shearer said ministerial credit card details contradict Mr McCully's statement that he was not informed about this until much later.
"What this shows is that he did receive an email straight after that Malaysian diplomat left the country.
"He said he did not pick up that email because he had no communication capability. What we've just found is that he was in New York which has considerable communication capability, but not only that, he had internet connection."
Mr Shearer told Radio New Zealand's Morning Report Mr McCully had always blamed his department but some of the blame should go to himself.