Prime Minister Bill English will stick to John Key's ban on ministers taking partners overseas on the taxpayers' purse, but says he will consider special cases and has already taken his own wife overseas on the Government's purse.

In 2009 Key told his ministers to pay themselves if they wanted to take their partners on official travel citing the economic downturn - and usually paid for wife Bronagh's plane tickets himself.

A spokesperson for English said it was not his expectation for partners to accompany ministers on overseas trips. "However, if there is a role for them we will consider it on a case by case basis."

She said Dr Mary English's trip with English to Europe in January was paid for by the government rather than English.

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Dr English attended a number of official events on that trip - including a reception at NZ House, a visit to Brussels war memorials and a wreath laying at Hyde Park in London

At the time Key passed the edict in 2009, the release of expenses was still new and Key was under fire because National had racked up $739,000 in international travel in its first three months in office - more than double the amount Labour spent in the same period the year before.

In newly released ministerial expenses from October to December last year those costs were over the $1 million mark, although lower than the high of $1.2 million for the quarter before that.

Key walked the talk by paying for Bronagh and his childrens' airfares out of his own pocket - but he could afford to.

That could have created a rod for his successors' backs - although it is expected Prime Ministers will take their partners or spouses on official overseas travel where they can be an important part of oiling the wheels of diplomacy.

Australian PM Malcolm Turnbull's wife Lucy came on his visit to Queenstown last week and the Turnbulls and Englishes went out for dinner and a walk.