Jacinda Ardern has been sworn in as New Zealand's prime minister - and says she will lead a government that is active, focused, empathetic and strong.

Jacinda Ardern will be New Zealand's next prime minister and hopes to take the country on a more liberal path after nine years of rule by conservatives.

The leader of New Zealand's Labour party conceded defeat to Prime Minister John Key's National Party in elections today, paving the way for him to return for a second term as the nation's leader.

The opposition National Party conceded defeat today in New Zealand’s general election and its leader said he expected Labour leader Helen Clark to form the next government.