The battle for the women's title at this year's State Paihia Classic on Saturday could be a showdown between an Aussie and a Kiwi.

Australian world champion, long-distance swimmer Melissa Gorman is picked to take the title after winning gold in the 5km open-water event at the 2009 World Swimming Championships.

But she is likely to face competition from Auckland elite swimmer Cara Baker who is swimming in the State Paihia Classic for the first time this year.

Queensland-based Baker out-swam defending champion Charlotte Webby of New Plymouth to claim the women's title at the 2.9 km Harbour Crossing in Auckland last month.

Webby won the women's title of the Russell-Paihia swim last year with a time of 40 minutes and 27 seconds.

Baker is one of many elite swimmers expected to use the 3.3km Russell to Paihia swim to build for the New Zealand Open Water Championships in January.

About 300 people have bought concession passes to compete in three or more of the swims that make up the State New Zealand Ocean Swim Series.

Event director Scott Rice says the Paihia swim is a popular swim in the six-event series.

Up to 65 percent of swimmers will travel from Auckland to take part in the event which the Far North District Council sponsors as part of an economic development strategy aimed at bringing visitors to the district.

He expects up to 800 people to take part in the 3.3km swim and shorter swims at Paihia Beach.

"The number of people who have registered for the swim is tracking above last year and is ahead of 2009 numbers which were nearly 700."

People have until midnight tomorrow (Thursday) to register for the event online at www.oceanswim.co.nz.

They can also enter in person at the Copthorne Hotel and Resort Bay of Islands Waitangi from 4-8pm on Friday.

People keen to see the first swimmers arrive at Paihia Beach should be at the beach on Saturday by 8am.

MetService is predicting mainly fine weather in the Bay of Islands on Saturday with a maximum temperature of 21 degrees and easterly winds.