"The 10km swims can take it out of you so you can't afford to peak for this weekend and expect to peak again in June and, if you are successful, peak for a third time in London. I have faith that I am in good shape and that I've done the work. Now I just have to put that into practice."
Leading Australians Trent Grimsey and Josh Richardson are in the men's field and 2009 open water 5km world champion Melissa Gorman is in the women's field. Gorman raced in last month's New Zealand ocean swim event in Paihia where she not only beat all of the women, but also all the men in that event.
Radford is glad to have some quality swimmers in the field.
"They will be using the race to test their training towards the Australian championships and so they will make sure the pace is on," he said. "I want a world-class pace, for sure."
Radford has not had much success over the 10km distance in recent times. He was second to Grimsey at the Oceania 10km at Lake Okataina in 2008, fourth at Taupo in 2010 and fifth last year. Across the Tasman he was seventh at the Australian 10km titles in 2009, eighth in 2010 and seventh last year.
Most of his success has come over shorter open water distances with victory in the Australian 5km championships last year, second in the New Zealand 5km along with two great wins in the prestigious Tiburon Mile in San Francisco in 2009 and last year.
There will be a major battle for the two men's spots for Portugal between Radford, Auckland's Phillip Ryan, his clubmate Jonathan Pullon, the Wellington pair of Isaac Foote and Casey Glover and talented teenager Stefan Talbot (Howick Pakuranga).
Ryan, 21, is the defending national champion over the 10km distance. He was third in 2010 (and second Kiwi), and edged out Radford at the Australian championships in 2009 and 2010, although he finished 13th last year. The Waterhole club swimmer is returning after injury last year.
Glover, 25, is another who has battled some shoulder issues, remedied he hopes with regular pilates. He has spent time under leading Australian coach Denis Cotterell on the Gold Coast as well as his Capital club in Wellington.
Glover was runner-up last year behind Ryan, and achieved the same placing in 2010 behind Australian George O'Brien. He warmed up with a third placing in the New South Wales champs last month.
Main Kiwi hopes in the women's race are the Australian-based pair of Cara Baker and Charlotte Webby.
The 10km championship is on Saturday along with the recreational swims, with the 5km national championships and New Zealand masters title decided on Sunday.