Dr William Tan has competed in the Paralympics, run in a marathon that spanned seven continents and hand-cycled across Europe.

But the Paralympian is expecting to break new ground when he goes on his latest adventure.

Next Tuesday (Aug 15), Dr Tan, 60, will take part in the Larapinta Trail challenge - the first time the wheelchair user will be setting out on unpaved terrain.

He said: "I've done a marathon in the North Pole, but this is gravel. It took me nine months to agree to do this."

The 223km Larapinta Trail is located in the Northern Territory but the five-day challenge will cover 65km. Sacred Aboriginal land can be found on parts of the trail.

Wheelchair users are not allowed on the trail but because the challenge is for a good cause, an exception is being made this time.

Organised by the University of Newcastle in New South Wales, the challenge aims to raise more than A$100,000 (S$108,000), which will go towards supporting indigenous education and health initiatives. Dr Tan studied medicine at the university and graduated in 2004. It was during that time that the issue caught his attention.

He said: "When I was two years old, I became paralysed from the waist down because I missed out on two drops of polio vaccine. The provision and availability of healthcare is an issue very close to my heart."

University of Newcastle director of advancement Rebecca Hazell said: "Dr Tan's inspiring story and determination will enable others to develop their talents and potential through the generosity of donors."

Dr Tan has been training for the Larapinta Trail challenge for about four months by going on the trails at the Bukit Timah Reserve because some of them share a few similarities to those in Larapinta. He said: "It's steep, uneven and undulating. There are rocks and pebbles. It's challenging enough."

That is in addition to his normal training regimen that includes working out in the gym in the morning and in the stadium in the evenings.

When he is not training or working out, Dr Tan puts his energy into his full-time job conducting health screenings for pre-school children in Mindchamps, among other things.

In 2009, Dr Tan was diagnosed with Stage 4 leukaemia and given only between nine and 12 months to live. It has been about eight years since the cancer went into remission.

He said: "I used to be very gung ho, but my journey against cancer made me realise how mortal I am... After being given a second chance at life, I maximise each day and do my best, as if it were my last."

On the Larapinta Trail, Dr Tan said: "I've trained really hard and I'm at peak fitness now. I feel confident and ready to go."

To donate, go online at larapintatrail.everydayhero.com/au/william-tan