The 200 strong convoy of classic pre-1978 specially reinforced vehicles, driving from the Barossa Valley to Darwin, is pushing hard to top last year's contribution of over $1.4 million.

"We are doing it for the Doctor, The Royal Flying Doctor Service who provide vital healthcare services to regional, rural and remote communities across Australia," Outback Car Trek organiser Bill Patrick said.

Participating in the annual trip for 15 years, he said he would be happy to match last year's donation, bringing the total raised to $30 million over the past 30 years.

Although the RFDS is best known for outback emergency retrievals, the majority of its work these days is facilitating vital primary healthcare clinics such as; mental and dental health, breast care, women and children's health, drug and alcohol counselling and chronic disease screening.

The outback trek has covered over 120,000 kms in the past 30 years, covering a different route each time.

"Being a pilot and having flown charter for the RFDS out of Wyndham, in the Kimberly, [joining the trek] was a no brainer," Carl Sever said.

"I've worked alongside the doctors and nurses doing medivacs and clinic runs to some of the countries most remote communities. I know what great work they do."

"I love the people we meet in regional and remote areas who quickly "ground" you with their generosity and open nature, despite enduring hardship we can't begin to imagine," he said.

The Outback Car Trek travelled into Darwin and the finish line at Vestreys beach today at around 2pm in sight of a major fundraising milestone.

Chief Executive Officer of the RFDS South Eastern Section, Greg Sam, said the contribution of the Outback Car Trek over the past 30 years has been immense.

"I would like to say a heartfelt thanks to all the Trekkers who have supported us over the past 30 years. It's an enormous achievement."

"The RFDS has a "waiting room" of some 7.6 million km sq and during the past year we flew almost 27 million kms to help over 335,000 people, which is the equivalent of one person every two minutes."

"One third of our funding comes from donated funds which helps to cover the cost of maintaining and upgrading our aircraft, infrastructure, medical equipment and facilitating our clinics."

While you're with us, you can now receive updates straight to your inbox each Friday at 6am from the Katherine Times. To make sure you're up to date with all the news, sign up here.