The four rowers who won gold in Slovenia and then finished fourth at the London Olympics are all unavailable for selection but Launceston cousins Ali Foot and Blair Tunevitsch lead the queue of willing replacements in a crew to be guided by Tasmanian Institute of Sport coach Brett Crow.

Foot and Tunevitsch have shown strong performances in the lead-up to this weekend's New South Wales championships, which will be a key step towards the selection of the Australian team for the first round of the world cup.

Nine lightweight men's pairs have been entered at Penrith and the Tamar clubmates, who were both reserves at the Olympics, are leading the way.

Of the four who competed in Bled and London, New Norfolk's five-time Olympian Anthony Edwards has retired, Lindisfarne's Sam Beltz has taken a year off but confirmed his intention to return next year, Ben Cureton has undergone a major back operation while fellow West Australian Todd Skipworth has become a professional triathlete.

``Skippy has not written off rowing but wants to see where triathlon can take him and that will influence his decision on whether to return,'' said Edwards, who has a joint development role with Rowing Tasmania and the TIS.

Foot and Tunevitsch showed great strength in a time trial in December and were 11 seconds ahead of the rest in a January training camp at the AIS.

``They are having a great season and with all the seats up for grabs in the boat Ali and Blair are in strong positions in a crew that will be made up of young talent that's been hovering in recent years.''

The NSW championship regatta, which began yesterday, sees the competitive return of 16 London Olympians.

Lindisfarne's 2008 Olympic champion sculler Scott Brennan is unavailable for selection due to injury, but intends to return for the 2013 world championship team selection trials.

Tasmania's best-performing London Olympian Kate Hornsey, of New Norfolk, is taking a year off along with her fellow women's pair silver medallist, Victorian Sarah Tait, who is expecting a child.

Returning Olympians Tess Gerrand (NSW), Renee Chatterton (SA), and West Australians Alexandra Hagan and Hannah Vermeersch lead the challengers targeting the vacant boat.

Depending on this weekend's results, rowers will continue the trialling process at Penrith next week with Rowing Australia selectors considering all boat categories for the world cup first round.