In some countries a litre of breast milk can sell for hundreds of dollars and while it's not commercially available in Australia, it could be soon.

Indian company NeoLacta Lifesciences was last year granted permission to start importing breast milk to Australia.

Dr Ben Hartmann, from PREM bank at Perth's King Edward Memorial Hospital, said pasteurised breast milk was being sold overseas for at least $300 a litre.

"It is quite an expensive product and overseas commercial services are providing milk at a higher cost than that," he said.

At the five breast milk banks operating in Western Australia, New South Wales, Victoria and Queensland, breast milk is donated by lactating mothers with excess supply.

It is screened and treated to feed very sick or premature babies in the neonatal intensive care units.

NeoLacta is one of only three companies in the world involved in processing human breast milk and it's contacted a number of Australian hospitals about supplying pasteurised and screened breast milk for use in neonatal wards.

Dr Hartmann said it could roll out into a more generally available supply, raising ethical questions about where Australia sources its donor milk from.

The company website states the promoters of NeoLacta ran a successful dairy business in Australia and it is offering bottles of "ready-to-feed human milk" made in a "world-class, pharmaceutical-grade facility".

Sorry, this video has expired NeoLacta Lifesciences was last year granted permission to start importing breast milk to Australia.

A milk run with a difference

Milk run: Kayla spends hours each week driving to pick up donated breast milk. ( ABC News: Sarah Farnsworth )

In Australia, breast milk banks do not provide milk for use outside a hospital setting, with limited studies into the benefit it has for full-term babies, but the informal sharing of milk has become a cottage industry online.

Thousands of women use Facebook pages such as Eats on Feets, Human Milk 4 Human Babies and the Australian Breastfeeding Project to find lactating mothers willing to donate their excess supply.

Body builders and cancer patients have also been known to seek it out.

Kayla with some of the donated milk she flew in from Sydney. ( ABC News: Sarah Farnsworth )

Kayla, a stay-at-home mum, sources breast milk online for her 11-month old son, Felix.

He was born with a posterior tongue tie and she struggled to breast feed him. She said he then had allergic reactions to formula.

She spends hours scouring websites for breast milk donors.

"It was more awkward for me at first because it's hard to ask someone to dedicate so much time that they could be spending with their baby to feed yours," she said.

Twice a week, Kayla does a 10-hour car trip to pick milk up from donors scattered all over Western Australia.

When donations recently dried up, she spent $450 flying in 30 litres of frozen milk donated by a group of mothers in Sydney.

"The 30 litres that came from Sydney lasted about two weeks" she said.

HIV, hepatitis could be present in breast milk

There are five breast milk banks operating in Australian hospitals. ( ABC News: Sarah Farnsworth )

Health experts warn HIV, hepatitis, syphilis and the Zika virus could all be present in breast milk, but there is only a small chance of transmission.

Neonatologist Dr Gillian Opie from Melbourne's Mercy Hospital said there were other risks associated with informal sharing of breast milk online.

"There has been testing done in the US to show that breast milk can be contaminated with illicit substances and other drugs like caffeine and alcohol," she said.

"It may be watered down, so not as nutritious as it should be."

Would you buy breast milk off the shelf?

Dr Ben Hartmann said there were ethical concerns with sourcing breast milk from low income nations. ( ABC News: Sarah Farnsworth )

Human breast milk is regulated as a food in Australia and falls under the Food Standards Australia New Zealand framework.

The Department of Agriculture, who granted NeoLacta's import permit, said it had tough biosecurity measures to ensure food products did not pose a risk to humans.

However, Dr Ben Hartmann said the regulation of breast milk was limited.

"One of the business models that we are seeing is the idea of sourcing the donor milk in a low-income country and selling it back to a high-income country," he said.

"There is no real regulation or governance of the process. It is up to the company."

In March, Cambodia banned the export of breast milk to the US by a company called Ambrosia Labs, after reports impoverished mothers were selling their milk to supplement their incomes.

"In Australia we may need to think about the risks and what duty of care we have to milk donors," Dr Hartmann said.