New Zealand's athletes showed big heart and top skills battling through big waves, competing against the world's best in the Trans-Tasman Surf Boat Challenge.

Australia's open surf boat teams and Under-23 teams each collected the most points in six rounds for each class, and took victory in both classes against New Zealand's crews, at Waihi Beach, after a hard-fought day of competition.

Surf Life Saving New Zealand Sport Manager Mike Lord watched the competition and says the Aussie teams had been top notch, but the Kiwis fought a strong fight.

'The New Zealand teams put up the best start, but then couldn't hold on and got hit back by some big gnarly waves that pushed them back. But that's the nature of the surf.”

The Kiwi men's and women's open teams each won their first rounds this morning, but then the Aussies came back and won the final two open races in both for men's and women's.

In the Under-23 competition, the Kiwi men's and women's team each won one of their three races.

'It was a good showing. The Aussies are awesome, they are definitely a world class crew, and they are great to watch,” Mike says.

'It was great to see the Kiwis right up with them, and beating them on some of the races.”

Conditions made the day 'challenging”, he says, with big waves adding unpredictable surprises during the competition, and forcing the athletes to fight hard for any distance gained.

'There were plenty of thrills and spills we saw,” says Mike.

'They're rowing backwards into big walls of water. It's four rowers and one sweeper on the back, in a boat, rowing back through the ocean, through the waves. They put everything into it, and it's pretty exciting to watch as they hit the waves.”

About 400 spectators watched the crews battle it out, with visitors from throughout New Zealand and Australia.

'The atmosphere on the beach has been awesome all day, and everybody's been looking out for each other in the water,” he says.

'It's definitely been a fun but challenging day for a lot of crews, and our officials have done a great job of picking up crews and gear out in the water.”

Two Trans-Tasman competitions were held on Saturday, the Trans-Tasman Surf Boat Challenge and Trans-Tasman Under-23 Surf Boat Challenge. Each competition consists of six races (three men's and three women's crew races for each), and a winner is decided by points.

This weekend round five of the six-round North Island Surf Boat Challenge is also being held at Waihi Beach by Surf Life Saving New Zealand. It was also held on Saturday and continues today.

This year all the Trans-Tasman crews were from Titahi Bay Surf Life Saving Club - the first time all crews have come from one club.

To see results from the Open Men's and Women's Trans-Tasman Challenge, click here.

To see results from the Under-23 Men's and Women's Trans-Tasman Challenge, click here.

To see results from the North Island Surf Boat Championships and Champion of Champions, click here.