Prime Minister John Key is defending the cost of a trip to Europe for five MPs.
The Speaker's Tour is a trip made every year, and this year's budget for travel and accommodation has been set at $158,000 to pay for visits to Britain, Croatia and Brussels.
Speaker of the House Lockwood Smith is leading the group, accompanied by his wife.
Also on the two-week trip are National MP Melissa Lee, Labour MP Darien Fenton, Green Party MP Gareth Hughes and New Zealand First MP Denis O'Rourke.
Before leaving, Dr Smith released a statement saying the visit will strengthen New Zealand's links to old allies and new friends in Europe during testing times.
John Key says the trip is paid for out of the Speaker's budget and, even in tight financial times, it is worth spending some money to engage with other democracies.
Labour's senior whip Chris Hipkins says political parties are well aware of the close attention the public pays to MPs' international travel and careful consideration is given to any trips taken.
"People look very carefully at the itinerary for trips before they put their names forward to go on them to make sure they can justify them.
"I think the days when an MP would go on a trip, have one or two meetings, say it was a work trip and then spend the rest of the time sightseeing - those days are well and truly gone now."