By Lucy Craymer

WELLINGTON, Oct 13 (Reuters) - Saturday is the final day to vote in the New Zealand national election, with the Labour Party seeking a third term and the centre-right National Party hoping to return to government with the help of coalition partners.

Advanced voting opened on Oct. 2. It is popular in New Zealand, with 68% voting ahead of the last election in 2020. The polls close at 7 p.m. NZDT on Saturday (0600 GMT).

National looks likely to win the largest proportion of votes in the election, but polls indicate that it will need at least one minor party, and maybe two, to form a government.

Voting in New Zealand elections is not compulsory but participation by eligible voters is typically above 80%.

WHAT IS THE STRUCTURE OF NEW ZEALAND'S PARLIAMENT?

Normally, there are 72 geographical constituency seats and then 48 seats are doled out to party-selected candidates, called "list members" in proportion to the overall public votes for each party. A party needs 61 seats for a majority.

The death of a constituency candidate means there will be an extra list seat allocated. A by-election will be held on Nov. 25 and from then, the total number of parliamentary seats will be 121.

HOW IS A GOVERNMENT FORMED?

Under New Zealand's mixed-member proportional system it is very uncommon for a single party to form government, although Labour did so under Jacinda Ardern in 2020.

If there is no majority winner, the major parties will start negotiations after the election and can either form coalition or supply and confidence agreements with minor parties. The party with the largest number of votes does not necessarily win, and negotiations can take days or weeks.

Under a coalition agreement, parties agree to be in government together. A supply and confidence agreement means they agree to support the major party but only in important matters such as a no confidence vote. Cooperation agreements, where the government agrees to work with another party even though it does not need its support, are also possible.

Ministerial positions for the minor parties may be up for grabs, and if a majority can not be formed, a second election will be needed.

WHAT ARE SOME LIKELY SCENARIOS?

Official results will be released on Nov. 3, which includes votes cast overseas. This has historically slightly changed the make-up of the government, and parties may wait to finalise agreements until these results are out.

In 2017, it took almost a month after the election before New Zealand First announced it would support the Labour-Green coalition. National, who held more seats, went into opposition.