All of New Zealand's Olympic-bound crews will all compete in the World Cup regatta starting in Lucerne on Friday night (NZ time), nearly two months out from the Games at Beijing.
Most interest surrounds Waddell, who hasn't competed internationally since winning gold in the singles at the 2000 Sydney Olympics.
He then switched codes, crewing for the Team New Zealand America's Cup yachting syndicate before returning to rowing late last year.
He launched a strong bid for the single sculls berth at Beijing but was beaten 2-1 by Mahe Drysdale in a highly-publicised duel in March, resulting in a change of boats for the Waikato giant.
Waddell has undergone 10 weeks of intensive training in the double scull with Nathan Cohen and while the duo have professed satisfaction with their progress, an indication of their Olympic prospects will finally come this weekend.
They are part of a powerful New Zealand team led by three-time world champion Drysdale and Olympic women's double sculls champions Caroline and Georgina Evers-Swindell.
Also looking for form will be men's fours world champions Hamish Bond, Eric Murray, James Dallinger and Carl Meyer, along with former men's and women's pairs world champions Nathan Twaddle and George Bridgewater, and Nicky Coles and Juliette Haigh.
Single sculler Emma Twigg, who won a bronze medal in the first World Cup regatta at Munich three weeks ago, will seek to go better this weekend.
The finals at will be raced on Sunday night (NZ time).
The New Zealanders will then prepare for the final World Cup at Poznan in Poland next month.
That regatta provides the last Olympic qualifying chance for a handful of New Zealand crews.
