Prime Minister Jacinda Ardern reacts to Boris Johnson's resignation

Prime Minister Jacinda Ardern is reassuring New Zealanders that despite the political instability in the United Kingdom, the two countries' strong relationship will continue.

It was just a week ago that Ardern was at 10 Downing St, meeting with British Prime Minister Boris Johnson and agreeing to extensions to each country's working holiday visas.

Since then Johnson's leadership has come under incredible pressure, with more than 50 lawmakers - including senior Cabinet members - resigning over concerns about his integrity. The latest in a long line of scandals, it emerged this week Johnson gave an MP a senior role despite previously being told the politician had faced sexual misconduct complaints. 

On Thursday night, Johnson announced his resignation as Prime Minister, but expressed his intent to stay in the role while a new Conservative Party leader is founded. 

In a statement on Friday morning, Ardern said she had "seen reports overnight from the UK around the transition to a new Prime Minister". 

"While obviously I won't comment on the domestic political affairs of another country, Kiwis should be reassured that New Zealand has an exceptionally strong relationship with the United Kingdom," she said.

"Over the course of our time in office, we've worked incredibly well with both Theresa May, and then Boris Johnson, securing an incredibly important Free Trade agreement with the UK. I fully expect this cooperation to continue."

Ardern joked earlier this week that Johnson's political turmoil was "in no way related to my recent visit". She had also previously met with May just days before the former UK Prime Minister announced her resignation in 2019. 

While chaos unfolded at 10 Downing St on Thursday night, New Zealand's Leader of the Opposition Christopher Luxon met with May at her office as part of an overseas trip to develop policy.

Johnson was a constant thorn in May's side when she was Prime Minister, criticising her strategy to deliver Brexit and positioning himself as her successor, which he ultimately became when she resigned after poor reception to her withdrawal plans.

But when it came to his turn to step down, May was filmed dancing the night away at a festival