"I was inspired by the story of the soldiers on the track; well they weren't really soldiers, they were just young Aussie blokes," Ms Milroy said.

"I just thought if those guys thought my life is worth fighting for, and I did not exist yet, then I have to make the most of what my life is."

Ms Milroy, a 33-year-old midwife, walked Kokoda to fulfil a long-held goal - and to raise money for Wollongong Hospital's birthing unit.

"I always had an idea that I wanted to do humanitarian work but trekking Kokoda really set my life path on a whole different track," she said.

"I have skills that I can use to make a difference to other people and I thought 'just do it, why wait for tomorrow?'

"I have done quite a lot since Kokoda - climbed [Mount] Kilimanjaro, trekked in northern Thailand and competed in triathlons."

Achieving her personal goals inspired Ms Milroy to apply to Medecins Sans Frontieres (MSF), also known as Doctors Without Borders, the leading international organisation for medical and humanitarian aid.

It is funded entirely by private donations from the general public. 

Ms Milroy is a nurse but said midwifery was her passion.

The rates of death in childbirth worldwide dismayed her.

"I thought, 'those numbers don't sit well with me. I have to do what I can'."

Her first MSF posting (October 2012 to April 2013) was to Papua New Guinea, where she was midwife at the Buin Health Centre, in Bougainville.

With caesareans requiring a seven-hour 4WD trip, and other clinical limitations, Ms Milroy said they lost babies they would not have lost in Australia but did not have a maternal death.

"The women [who lose a baby] are equally devastated ... but unfortunately they are more used to it [than Australians].

"No matter where you live, it is still not OK to lose a child."

Ms Milroy said the extended family network she saw in action was, in many ways, preferable to how western culture deals with the same loss.

"That was just amazing . . . they would come to hospital to take the mother home - and I am talking 20 to 50 people; the village would come to the hospital. I can see how that social support made such a difference."

As well as her midwife role, Ms Milroy was also part of a team targeting gender-based violence - sexual, emotional and physical abuse - something she said was a significant problem on Bougainville and the PNG mainland.

Ms Milroy said stories such as that of a woman who had been attacked by her husband with a machete, causing wounds to the bone, would stay with her.

"It is a taboo topic," she said. "You would have women coming in to the hospital who had been victims of a lot of physical violence and that was really distressing for me.

"They don't have a social system where they can go to a women's shelter, or have a legal system where they can get custody of kids.

"It's either deal with this or get out, but they don't get out because they don't want to lose their kids. You can fix their wounds but you can't fix their social position and that was hard."

While emotionally challenging, Ms Milroy said the low-security PNG project was a test of whether MSF was what she wanted to do as "a lifestyle choice".

She left for her second posting last week - to work with Syrian refugees in Jordan - again for six months.

While Ms Milroy can foresee a time when she has her own family, she said for now she was inspired to keep doing what she could in the field, and if circumstances changed she hopes she could still work for MSF in Australia. The Kokoda track helped her find her calling.

For more information about Medecins Sans Frontieres visit the msf.org.au website.