Successful swimmers then move on to the BHP Billiton Aquatic Super Series in Perth on February 1, where they will need to finish in the top six of Australian and New Zealand swimmers to automatically secure qualification for the world championships.
Rotorua's Radford, who is based in Perth, will be chasing his fourth straight national men's title in the 10km event. The 24-year-old won a bronze medal at the Pan Pacific Championships and will be looking to stamp his class on the field, which features an all-Kiwi line-up.
His major challenges will be expected from the 2011 national champion Phillip Ryan (Waterhole), Waikato's Troy Balvert (St Peter's), and Wellington's Liam Albery who was fourth in the junior Pan Pacific Championships in Hawaii.
Webby, 26, is the hot favourite to claim the national honours in the women's 10km race today, with last year's leading Kiwi, Grace Somerville, missing this year.
The Taranaki swimmer took the official national title with Somerville racing in the junior division, and went on to finish an encouraging sixth place at the Pan Pacific Championships in a strong field led by Olympic medallist Haley Anderson (USA).
Webby will be challenged by Penelope Hayes (St Peter's) and Bridget Maher (West Auckland Aquatics) amid a small field.
That's not the case for the bumper entries in the recreational swims that form part of the sixth Epic Swim event which has attracted a record 850 entries, nearly trebling since the first event in Taupo in 2010.
The 10km New Zealand Championship is on this morning along with a range of recreational swims from 100m to 10km, with the five km national championship and a masters race on Sunday.
