The Upper Murray's largest event kicked off on Thursday with the first rounds of its marquee event to begin Friday with O'Shea among a combined 72 male, female, veteran, junior and rookie competitors shooting for $80,000 in prizemoney.

They will test their skills in events including bareback riding, horse shoeing, whip cracking, stock handling and cross-country before the challenge finalists are announced on Saturday night.

The final includes the time honoured brumby catch.

O'Shea has accumulated enough points in recent years to contest the open event at Corryong which was won by Tooma horseman John Mitchell for the first time last year.

Her latest win was in last month's King of the Range held in the Upper Hunter Valley.

The male winner of the event held at Murrurundi was Bronson Macklinshaw, who won the Man From Snowy River Challenge two years ago.

The previous female rider to win three challenges in a row was Christy Connor between 2007 and 2010 with the 2008 event not held due to the equine influenza outbreak.

Jocelyn Paton is a four-time challenge winner including three victories in a row between 1996-99 which was soon after the event's inception.

Mitchell's brother David is also a past challenge winner and both will be competing again this weekend.

Another highlight of the event which attracts an estimated 20,000 people is the Man From Snowy River re-enactment at nearby Thowgla.

It also coincides with the arrival of the Riley's Ride participants from four days of tracing the final journey of the legendary Jack Riley.

Festival co-ordinator Jenny Boardman said: “We are so proud to be able to celebrate our unique bush heritage and its culture here in Corryong every year and cannot wait to kick off what our hard-working community has brought together.”