The cancellation today, put down to "slow heating" by event organisers, follows those on days one and four and the abandonment of competition in the 15 metres and 18m classes on day two.

The 15m class was also cancelled yesterday, following a mid-air collision involving Australia's Stephen O'Donnell and Germany's Michael Eisele.

More details have emerged regarding the accident, which happened over Yerong Creek en-route to Narromine.

The two pilots, both of whom were forced to bail out of their aircraft and parachute to safety, were taken by helicopter to Canberra hospital, where they were treated for minor injuries.

According to The Border Mail, Eisele was treated for a fractured ankle, while O'Donnell suffered a back injury.

The incident, which occurred at approximately 5,000 feet, is being investigated by the Air Safety Bureau.

"Both pilots bailed out of their aircraft and used their emergency parachutes, which is what they are there for," Championship spokesman Sean Young, a Gliding Club of Victoria member, told The Border Mail.

"Both of them were taken to Canberra hospital for treatment.

"They've each taken a heavy fall when they've landed, but fortunately the injuries they have aren't too serious.

"Other competitors in the Championships have been informed of what has happened.

"Everyone knows what is going on."