Opinion - Just days before the new Labour-New Zealand First-Green Government gets sworn in, political opponents are suggesting it is somehow not legitimate.

Photo: RNZ / Richard Tindiller

The National Party's new Northland MP Matt King, in a now deleted Facebook post, described it as an "arrogant grab of unmandated power". He said the new government had no moral authority because Labour had received fewer votes than National.

National's leader and outgoing Prime Minister Bill English says he accepts the legitimacy of the result. But he, too, has cast some doubt on the new government. He told Morning Report this was the first time in 100 years that the most popular party did not end up in government.

But Mr English is wrong.

As recently as the 1978 and 1981 elections National won fewer votes across the country than Labour but won more seats in the first-past-the-post electoral system. So for six years it governed while the marginally more popular Labour Party sat on the opposition benches.

Some National Party supporters, however, appear to think the party was robbed this election and that just seven percent of voters - those who voted for New Zealand First - determined the final outcome. They forget, of course, that both Labour and the Greens also had to sign up to the deal to form a new government. And had New Zealand First thrown its support behind National would the argument had remained the same?

National deserves to be disappointed that its strong result in the election did not end in it leading a fourth-term government. Achieving 44 percent in any circumstances, let alone after nine years in power, is a strong result.

There is little need for the party to review its election performance. Its leader Bill English ran a good campaign and surely put to rest the ghosts of National's disastrous 2002 campaign when, under his leadership, it recorded its worst result with just 21 percent of the party vote.

But National failed to adapt to MMP. To form a government, it is not enough to win most votes. Parties must be able to form partnerships with others to govern.

From 2008 to 2017 it relied on its own strong vote and support from the Maori, ACT and United Future parties to govern. But National was always going to need more support this election. Yet it did nothing substantial to develop a relationship with New Zealand First. In the end, too, there was simply more policy alignment between NZ First and Labour.

Go back to the 1978 and 1981 elections when National won marginally fewer votes than Labour. That result, coupled with Social Credit's failure to win more than two seats in 1981 despite a 20 percent popular vote, helped fuel the campaign for electoral reform. Both those National Governments led by Robert Muldoon governed with support of less than 40 percent.

In contrast the new government being sworn in on Thursday not only has a majority of seats in the Parliament but also the support of 50.4 percent of those who voted in the 23 September election. Between them National and ACT have 44.9 percent support.

There is no question this is a legitimately elected government. Whether it is an effective government which meets the ambitions of its different groups of supporters only time will tell.

In 2020 Matt King will get the opportunity to put to the test his belief that it was an "arrogant grab of unmandated power" - just as Labour, New Zealand First and the Greens will find out for sure if the 2017 result really was a vote for change.

*Brent Edwards is a former RNZ political editor.