"Finding a way to win is positive, but our execution was not up to standard.

"We deviated from our game plan, leaving us somewhat let down. Lack of sharpness cannot be blamed.

"This serves as a wake-up call that the players will recognize. We battled back, so we can build on that with areas for improvement."

New Zealand appeared set for an easy win after Stacey Waaka's early try in the second minute, yet Fiji improved and crossed after 21 minutes.

Captain Sereana Naitokatoka broke from dummy half to set up Losana Lutu for Fiji's opening try in the women's World Cup.

Five minutes later Sienna Laing added another, making an upset possible.

Waaka grabbed her second before halftime to reduce the deficit, but Fiji's defense held firm after the restart.

New Zealand equalized and then led through Zehara Temara's penalties under mounting pressure.

The result was sealed late when Raecene McGregor's kick was gathered by Leianne Tufuga for the try.

"We had no preconceptions, but they competed freely," New Zealand's Georgia Hale noted. "They certainly challenged us.

"We had command but then lost it with uncharacteristic errors and poor discipline.

"Our aim was simple: to set the tone physically and advance the ball, but we strayed from that identity.

"We had to fight hard to recover. It came down to fortune ultimately."

Next, New Zealand host France in Christchurch in Group B, while Fiji meet Papua New Guinea.

Meanwhile in the men's World Cup, Fiji began strongly by beating Cook Islands 40-12 in Newcastle.

Both teams are in Group A with hosts Australia and New Zealand, facing a challenge to reach the last four.

Fiji's preparation was rocky, seeing Mick Potter take over from Wise Kativerata as coach amid internal issues, and captain Tui Kamikamica retiring due to a stroke in March.

They boosted morale with a solid victory, scoring seven tries and 34 straight points before Cook Islands replied late.

Fiji next play defending champions Australia, hoping to outperform their women's side with a big shock.

"We will prepare normally," Potter said about facing Australia. "It is essentially a two-team contest for the title in my view, offering a chance to cause an upset."