By Charlotte Greenfield

WELLINGTON (Reuters) - Support for New Zealand's National Party has surged, a poll published on Tuesday suggests, indicating the ruling party will grab enough votes at looming national elections to govern.

The Newshub-Reid poll is the latest twist in the rollercoaster ride of New Zealand's electoral campaign, coming just weeks after a separate poll showed support for the opposition Labour Party surging above the Nationals.

That had given rise to speculation that Labour would return to power as the lead of a coalition government after almost a decade in opposition.


The unusual volatility has been giving investors jitters.. The New Zealand dollar, the 11th most traded currency in the world in 2016, jumped to $0.7265 after the poll was released from $0.7224.

The Newshub-Reid poll showed backing for the National Party up 4 points at 47.3 percent and, in a double whammy for Labour, showed the opposition party's support down 1.6 points at 37.8 percent.

"It's a huge setback for Labour," said Bryce Edwards, Wellington-based analyst at Critical Politics. "It really just shows how volatile this election campaign is."

The National Party has vowed to support free trade as global protectionism rises, in particular, by championing the Trans-Pacific Partnership pact, which Labour has said it would renegotiate.

The surprisingly strong result for National suggested it might not need the nationalist New Zealand First Party, long considered the likely kingmaker, to form a government at the Sept. 23 election.

Labour changed its leader last month in a bid to jolt life into its struggling campaign, appointing 37-year-old Jacinda Ardern. That last-minute gamble had appeared to be paying off with Labour climbing dramatically in previous polls. An average of previous polls, compiled by Radio New Zealand on Friday, showed Labour's support had surpassing National's.

The latest Newshub-Reid poll suggested that the two minor parties traditionally needed to form a coalition government would not have a role to play this time around.

New Zealand First, led by populist politician Winston Peters, slipped 0.6 points to 6 percent. The Green Party, which is aligned with Labour for a potential coalition, fell to 4.9 percent, below the 5 percent threshold needed to gain seats in parliament.

(Reporting by Charlotte Greenfield; Editing by Jane Wardell and)