Climate Change Minister Nick Smith was called a liar in Parliament on Tuesday as MPs argued over the cost of the Government's Emissions Trading Scheme.
Labour Party finance spokesperson David Cunliffe was forced to apologise for his remarks after Dr Smith objected.
Radio New Zealand's political editor reports Question Time got heated as Dr Smith and acting Prime Minister Bill English rejected Labour accusations that the scheme would impose greater costs on taxpayers.
It ended with Dr Smith objecting to Mr Cunliffe calling him shifty and accusing him of not telling the truth. Mr Cunliffe did apologise.
Earlier, Dr Smith said that the Emissions Trading Scheme would not cost taxpayers' billions of dollars.
In fact, the minister says analysis by the Treasury shows it will save about $100 million by 2018.
Dr Smith tabled the analysis, but it turned out to be a single page of figures prepared by the Ministry for the Environment.