Housing Minister Phil Heatley says he is embarrassed and upset about slip-ups involving taxpayer-funded credit card spending outside ministerial rules - gaffes which have annoyed Prime Minister John Key.

Purchases made outside Parliamentary rules by Mr Heatley and fellow minister Gerry Brownlee were brought to light in the Dominion Post today, which said it raised questions over why such purchases were being rubber-stamped by Ministerial Services.

Mr Heatley said he would repay $906.80 in travel, accommodation and meal costs for him and his family for the duration of a South Island visit which included a conference and trip to Kaikoura's Whale Watch, and had paid back $175.30 for food and drinks purchased at a National Party conference in Christchurch last year. He had since questioned his decision to take his family on the trip.

Mr Brownlee repaid $151.90 spent in September for lunch with electorate staff in Christchurch.

Mr Heatley was questioned by media today about buying movie tickets and fast-food with the ministerial card.

He said the tickets purchase was simply a case of using the wrong card by mistake and he repaid the money soon afterwards, while the fast-food purchase was a case of not being clear about the rules for using the card.

"I should have known the rules much better around the credit card use, and it has cost me dearly."

Mr Heatley said he was doing a good job of overseeing his ministerial portfolios, including fisheries, and had not considered resigning.

Mr Brownlee said he admitted he made a wrong decision to pay for the electorate lunch. He said he was "deeply embarrassed" and would only use his own credit card from now on.

Prime Minister John Key said it was up to all ministers to be aware of the spending rules, and that they had staff to help with that.

The spending errors brought to light were "silly mistakes" and he had made his disappointment clear to the ministers in question and didn't expect them to make the same mistake.

Mr Key said he acknowledged the spending slip-ups were rubber-stamped by Ministerial Services, but the main onus was on individual ministers to ensure they stayed within the rules.

Labour leader Phil Goff questioned how MPs with large portfolios could expect to be trusted when they were incapable of looking after their own expenses.

"I think it shows poor judgment but it also will make New Zealanders angry because while they are struggling to make ends meet they don't want to see ministers using their credit cards to pay for alcohol for their mates."

Mr Goff said Mr Key's ministerial management over his colleagues and Ministerial Services needed to be cleaned up.

Mr Brownlee said he had handed in his ministerial credit card and Mr Heatley said expenses would be handled by staff from now on. Both apologised over the issue.

MPs' and ministers' expenses came under intense scrutiny last year with the first ever disclosure of the MPs' claims for travel and housing expenses.

Some MPs paid back tens of thousands of dollars spent on housing in Wellington and travel for themselves and their partners.

Mr Key then ordered a review of housing allowances, which resulted in adjustments in spending rules.