"I think those three things combined have meant we've had really good turnouts. We've raised about $150,000; $100,00 to our major charities and at least $46,000 that have gone out to local orienteering clubs and schools."
This year's challenge will be the last event, and Ms O'Sullivan couldn't help but feel a "tinge of sadness" that the annual series was drawing to the finish line.
"We're certainly going out with a bang. It's completely sold out and will be our highest numbers yet. We've got 878 people registered which is fantastic and it's great to see so many people wanting to do the event."
She hoped to raise in excess of $14,000 for merino packs to be given to the Hawke's Bay Hospital for mothers with newborns.
"It has been fantastic. We've had a lot of support to do the work; local organisations and councils have supported us and we've had an incredible amount of support from our staff. In turn we've been able to give a lot back to charity which is really important to us."
Kicking off at 7am the Staples Rodway Challenge will be starting and finishing at Clifton Bay; covering mainly private land including beaches, forests, waterfalls and coastal farmland.
The first leg for this year's race is a beach run at Cape Kidnappers before the next leg takes participants into Cape Sanctuary.
The third leg leads to the Maraetotara River before the race concludes at the Clifton Cafe.
A prizegiving will be held at the cafe at 3pm and Ms O'Sullivan said everyone, not just those who had registered, were welcome to join the event.