All 35 curling clubs in the country have been invited to send a team and up to 270 curlers are expected to converge on Oturehua to take part in the sport's most coveted competition.
"Everything goes on hold for those two days because the national event is the pinnacle of competition for curlers.
"It's what everyone looks forward to, because it doesn't happen very often," New Zealand Curling Association chairman Robert Rutherford, of Poolburn, said yesterday.
A succession of frosts coupled with a "good" forecast of more frosts, added up to a buzz of anticipation for curlers.
It will be the first since the national bonspiel in 2007, which attracted a record number of competitors, and is only the third such event in the past 14 years.
The dam had 12cm-13cm of ice now and "it's a beautiful bit of ice," curling association ice master Stewart McKnight, of Ranfurly, said.
"The big outdoors event gets people excited and there's certainly a bit of a vibe happening."
Three ice-masters - Mr McKnight, Mr Rutherford and Murray McKnight, of Oturehua, make the decision on whether to call a bonspiel, based on the depth of the ice and weather forecasts from several different sources.
Curlers get just 48 hours' notice of the event so they can arrange time off work and plan around the bonspiel.
Mr Rutherford expected 33 clubs to be represented.
Most teams travel from Canterbury, Otago and Southland.
A couple of Auckland curlers competing in the national curling championships at the indoor rink in Naseby at the weekend were also staying on in the hope of experiencing the ultimate in the outdoor game.
Mr Rutherford said the Idaburn was covered in strong "black" ice which was better than snow ice, formed with a mix of snow.
Little needed to be done to prepare the ice surface for competition.
"There's no snow in this mix, just a succession of good frosts, so it's good and hard," Mr Rutherford said.
"Mother Nature has looked after us pretty well."
He hoped the curlers' good fortune would continue and the frosts forecast for the next few days coming to fruition.
"The last thing we need is a wind change.
"If it's a southwesterly that's good, but a northerly wind change would be disastrous and soften the ice up."
Rough Ridge is the defending national champion and will have a team of eight defending its title.
Competition will take place from 9am to 5pm each day, with each team playing two games each day.
A series of trophies are at stake, with the "Snuff Box" trophy for the overall champion.
The Idaburn Curling Council will host the event and 35 rinks will be marked out on the ice today. lynda.van.kempen@odt.co.nz
