New Zealanders expect to learn Thursday if their next prime minister will be 37-year-old liberal challenger Jacinda Ardern or 55-year-old conservative incumbent Bill English.

The maverick leader of a small party that holds the balance of power said he would be making an announcement.

New Zealand First leader Winston Peters, 72, is expected to declare which of the main parties he favors joining in a coalition.

New Zealand First has been negotiating privately with Ardern's Labour Party and English's National Party after an election held nearly a month ago ended without a clear winner.

Peters is expected to extract policy concessions and some ministerial posts from either party he chooses. He told reporters on Thursday that making a decision has been "seriously difficult."

His party's policies are nationalistic and eclectic.

He wants to drastically reduce immigration and stop foreigners from buying farms. He opposes plans by National to increase the pension age and plans by Labour to tax certain water users.

National has held power for the past nine years. English says his party has grown the economy and produced increasing budget surpluses which benefit the nation.

He said he thought National could form a strong government with New Zealand First.

"Mr. Peters has indicated that he's going to announce his position later in the day and, like everyone else, we look forward to hearing what it is," he told reporters.

Ardern says she wants to build thousands of affordable homes to combat runaway house prices, spend more money on health care and education, and clean up polluted waterways.

Under New Zealand's proportional voting system, larger parties must typically form alliances with smaller parties to govern.

A coalition needs at least 61 seats to hold a majority in the 120-seat parliament. National won 56 seats while the liberal bloc of Labour and the Green Party won 54. New Zealand First won nine seats.