Drysdale challenge's Martin for Billy's trophy

Mahe Drysdale will be back for the Billy Webb Challenge on December 11.

A rematch of one of the greatest finishes in the history of Olympic rowing could play itself out on the Whanganui river next month.

The sixth event of what is now the annual Billy Webb Challenge has been confirmed for December 11 with multiple-time defending champion and Rio Olympics gold medallist Mahe Drysdale back for another go.

The challenge was changed from a biennial event to being held every 12 months for the first time last year, with Drysdale winning an amanda-style race in 2015.

Event director Bob Evans said they would try to keep the format of every second year being an "all-star" race for single scullers, and Drysdale has taken up that mantra by inviting his Croatian rival Damir Martin to join him this year.

In a stunning single sculls final on the Rodrigo de Freitas lagoon in Rio de Janeiro, Drysdale, 37, held off Martin in a tense finish which was so close that the electronic television monitor initially gave the race to the 28-year-old European champion.

After photo-finish analysis, it was revealed Drysdale had won by half a bow ball, with both men posting the identical time of 6m 41.34s in an Olympic record.

"Among other single scull rowers, [Drysdale] has put out the challenge to Damir Martin to come and fight back," said Wanganui Rowing Association spokeswoman Kate Austin.

"Competitors in the race will be racing Mahe over a 5km course on the Whanganui river.

"The race is open to all rowers who want to take on the famous pair in New Zealand's premier single scull race."

The challenge will be held on the Sunday after the Jury Cup regatta, which will also draw many rowers from around the country.

In addition, the corporate eight race will be held again before the main event

"Wanganui businesses are encouraged to get together a crew, find a coach and a boat to compete in the fun event.

"The event has been a success in previous years."

The challenge has been run since 2008, which marked the centennial of Billy Webb successfully defending the world single sculls title on the Whanganui against Australia's Richard Tresidder.