Jacinda Ardern's emotional wedding surprise

Labour's deputy leader Jacinda Ardern has taken time out from politics to make a dash half-way around the world to surprise her sister the day before her wedding.

Ardern's only sister lives in London, and the Mt Albert MP had previously made the tough decision she couldn't attend the wedding, given the election is less than three months away.

However, as the day drew closer she said she knew she had made a "massive mistake" - so after getting the green light from leader Andrew Little booked last-minute tickets.

Yesterday Ardern posted a video of her surprising her sister on her Facebook page. It has already been viewed more than 100,000 times.

"Today I walked my beautiful sister down the aisle, and I feel so privileged and lucky to have been able to do that," Ardern wrote.

"P.S Thanks to my colleagues for covering for me, thought the least I could do is share the surprise."