A $5000 donation from the Australian Turf Club to a fundraising trek along the Kokoda Track has been met with gratitude and extra-big grins during a presentation at Rosehill.

Jockeys Hugh Bowman, Kathy O'Hara and Corey Brown, who are among a group of five walking the Papua New Guinea trail next week for two charities, were on hand to accept an oversized cheque when a rather large error was noticed.

The novelty sign had been written out for a mere $500.

Officials quickly rectified the situation on stage before all involved retook the celebration photographs - with much bigger smiles than before.

Victorian-based jockey Stephen Baster and model Kris Smith are joining Bowman, O'Hara and Brown for the four-day hike, which is a key fundraiser for the National Jockeys Trust and brain cancer charity Mark Hughes Foundation.

Some have close links to the Australian military, particularly O'Hara, whose parents both served, and premier Sydney jockey Bowman, whose great uncle died in the Southeast Asian theatre of World War II.

Donations can be made at walking2help.com.au.