Jacinda Ardern has received a message of support from her British counterpart Jeremy Corbyn.

The UK Labour leader endorsed Ardern in a video posted on Twitter by TVNZ broadcaster Jack Tame.

"Jacinda, all the best in the election," Corbyn said. "Make sure you do it - for all of us."

Like Corbyn, Ardern has completely turned around Labour's fortunes, helping to the gap with National ahead of the election.

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In one poll, she has helped Labour rise 19 points and overtake National as the most popular party.

When British Prime Minister Theresa May called a snap election earlier this year, the UK Labour Party trailed the Conservatives by around 20 points.

But under Corbyn, it closed the gap to one of the closest elections in 40 years and Labour ended up with 30 more seats.