The dam has lost about 5cm of ice in the past two weeks, when snow was followed by northwest winds and mild temperatures.
New Zealand Curling Association ice master Stewart McKnight said it would be hard for the amount of ice lost to reform this far through winter.
"There have been bonspiels in August but those were during years where there was an awful lot of ice. The prospects of a national bonspiel this year are now pretty remote," he said.
At least 10cm of black ice is required to hold about 150 people on the dam, and more than 12.7cm would be needed for a national bonspiel - which in 2007 comprised a record 270 curlers.
In the first weeks of July, almost 15cm of ice formed on the Idaburn dam, raising the hopes of curlers throughout New Zealand.
An Idaburn Curling Council bonspiel was called and promptly cancelled on July 1, after forecast frosts never eventuated.
The council's 16 curling clubs played for the Wilson Cup in a one-day bonspiel on July 14 instead, although disruptive weather had scotched all other bonspiel attempts since.
"We were so close," Mr McKnight said.
On Friday, representatives of clubs in the Idaburn and Naseby curling councils will compete for the Idaburn Trophy on artificial ice at Naseby.
Mr McKnight said the curling tournament would take place on four rinks at the Maniototo Ice Rink, after which curlers from throughout the country would gather for a traditional "beef and greens" dinner and a curlers court at Oturehua.
More than 100 people were expected to attend the dinner and court at the Oturehua Hall, where brother and sister curlers (those already initiated into the secret curlers court), would welcome young members.
"We try to have a curlers court every second year even if there isn't a national bonspiel. All curling clubs throughout New Zealand are invited", Mr McKnight said.
The last curlers court was held in Oturehua on July 17, 2007, following a two-day national bonspiel on the Idaburn dam.
