New Zealand have retained the America's Cup with a 7-2 win over Britain, after a performance that prompted defeated skipper Ben Ainslie to label them as the "best team ever".

The victory makes it a third win in a row for New Zealand, who again lifted the "Auld Mug" which they had won against Italy in Auckland in 2021 and against the US in Bermuda in 2017.

There were hugs among the victorious crew of eight on board "Taihoro" on Saturday before the sleek AC75 headed back to shore with an armada of supporter boats, horns blaring and flags fluttering, for a traditional Maori welcome.

"It's a pretty surreal feeling for me," New Zealand skipper Peter Burling said before going for the prize-giving ceremony as evening drew in on the Barcelona waterfront.

"I'm looking forward to hoisting the trophy ... it's going to be an incredibly special moment. It doesn't really feel like you've won the America's Cup until you've done that," he said.

New Zealand's America's Cup win marks a successful finale to a three-year campaign to retain the trophy, which is billed as the oldest in international sport.

Burling became the most successful helmsman in the event's 173-year history in the course of what he called an "incredible campaign".

But he also praised the British challenge, adding: "We felt like we needed to bring our A-game racing them and I think we are really proud of how we did that as a group."

"I'm not sure what the future holds, but I'm sure it will be something exciting," Burling said when asked about getting involved in another campaign to defend the huge silver trophy.

Britain's Ainslie paid tribute to the Kiwis after losing out in a tight skirmish when 6-2 down in the first-to-seven series.

Britain has never won the America's Cup, which began in 1851 with a race around the Isle of Wight off the south coast of England, and Ainslie has now tried, unsuccessfully, three times.

"We set this thing up 10 years ago to win the Cup, and I'm not a quitter," Ainslie said, when asked if he would keep trying to "bring the Cup home".

Asked if he would be helming the boat in the next attempt, the 47-year-old said he would do what was right for the team.

"I don't know next time if I am going to be on the water or not, but I am committed to the team moving forwards and ultimately to getting the job done and winning the Cup," said the most successful sailor in Olympic history.

Ainslie's attempt this time, with the backing of British billionaire Jim Ratcliffe, cost more than Stg 100 million ($A195 million) and involved the Mercedes Formula One team.

"Jim's definitely behind the team," Ainslie said, adding that it would be good to bring in other partners or private support for the next campaign.

He also confirmed that the British team would be the "challenger of record" for the next America's Cup, which means that they get to negotiate key parameters with the holders.