The group, which has more than 80 athletes on its database, is concerned about the threat to swimmers' safety posed by boats.
Although no conflicts have been reported so far this summer, the group has renewed calls first made last summer to remove a ski lane from the area, arguing it is in shallow, rocky water which does not appeal to most water skiers.
Two of the group's organisers, Claire O'Connell and Anna-Kate Hutter, said this week the campaign aimed to prevent accidents and educate people about the potential for conflict, especially over the holidays when many visitors would take to the water.
The group wanted to help with safety issues because it had grown so large, swimmers now wanted to "go longer", swimmers were not contained by a 200m buoy line put in last year and they could be swimming anywhere in the lake.
"It is time to give them a couple of kilometres . . . that [buoy line] has proved its point," Mrs Hutter said.
The extension would not have to be marked with buoys every 10m, she said.
"That is not very attractive and could also imply we are not allowed to swim outside those buoys," she said.
The intention was not to confine swimmers to that area but to help create a safe situation for those who felt less secure in the water, Mrs Hutter said.
Wanaka Community Board chairman and councillor Lyal Cocks said yesterday he had noticed more lake swimmers than ever before but had not realised the database now held at least 80 names.
He hoped to meet Mrs O'Connell and Mrs Hutter this week and would also seek a report from harbourmaster Marty Black.
"I am totally supportive of swimming.
We will look at the lane again," Mr Cocks said.
Wanaka Yacht and Power Boat Club Commodore Ken Urquhart said he supported a non-motorised zone in Roys Bay and wanted to share training and race schedules with swimmers.
Tension from an incident last summer, when a swimmer got in the way during a yacht race, had been resolved; he noted that swimmers using the pink yacht club buoys as "targets" was not advisable, especially on Thursday race nights.
Mr Black said yesterday he was not promoting the extension because people had told him they were using the ski lane.
It was recently reduced to less than 100m.
He believed education and communication should continue.
"Boats are supposed to be 50m away from a person in the water. That should be good enough protection but unfortunately you are sometimes dealing with people who don't think," Mr Black said.
He suggested long distance swimming groups tie inflatable 1m high "sausages" to the front and back swimmers.
Other common safety practices included wearing bright caps and having support boats or kayaks in deep water.
Meanwhile, Mrs O'Connell has set up a blog so swimmers can share information with other lake users.
The address is: wanakalakeswimmers.wordpress.com.
