So it remains a slight mystery as to how a family, travelling through the outback in a dated caravan, was able to single out a tree for their project.

But they did, and now they may hold claim for being the first to bring the growing mental health awareness campaign - The Blue Tree Project - to the Territory.

For months now, a single blue tree on the Stuart Highway, close to the small town of Mataranka, has been a puzzle to many - including its Mayor.

The colour was a clear link to mental health, but unless you were prepared to stop on the busy highway and take a close look, you might not have known much more. And when it was painted was definitely up in the air - until now.

The paint job was part of a wider family challenge for Liam, Amanda and their four year old son Banjo.

"We were going to have a lot of spare time on our hands, and we wanted to set a good example of what can be achieved for our son," Liam said.

"It is easy to sit back and complain about how things should be, but it doesn't take much to be a part of the solution."

The challenges started in January last year, at the beginning of their trip - one per month.

First it was the #trashtag challenge in Broome, where they filled dozens of bags with litter, then they raised hundreds of dollars for the not-for-profit Feed the Children.

In may, the threesome walked 50 kilometres through the Kimberly to raise money for multiple sclerosis.

A plumber by trade, Liam donated labour while the family visited the Tiwi Islands.

"We had just done the walkathon for MS and we were looking for a June project," Liam said.

"We had heard about The Blue Tree Project and began searching for the perfect tree as soon as we left the Kimberly.

"The local Mitre10 in Kununurra donated blue paint and brushes, but we didn't find anything suitable until we were camping on the Stuart and we were on a walk.

"It had to be close to the road, and we didn't want to tackle anything too big, but we found it. It just felt right."

It took the three of them hours to cover it in blue - Liam had to stand on the top of the car to reach high into the branches.

"Everyone knows someone impacted by mental health or depression, Amanda and I personally have friends who have taken their lives, so the cause is close to us," Liam said.

"It appears to already be doing what it was intended to do: build awareness, get people talking.

"It is a long stretch of highway with plenty of time for conversation."

While the family has been travelling for about two years now and are on the home stretch - wherever that may be - Liam says the challenges will continue.

Roper Gulf Mayor, and Mataranka resident, Judy MacFarlane, said while it may have taken longer than expected, the remote and isolated town, with a population of about 350, is beginning to take much-needed notice.

Find out more about The Blue Tree Project here.

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