Utah-based company Ambrosia Labs claims to be the first of its kind to export human breast milk sourced overseas into the United States for mothers who want to supplement their babies' diets or cannot supply enough of their own milk.

The milk is collected in Cambodia, frozen and shipped to the States where it is pasteurised and sold by the company for $20 each 5 oz (147 ml) pack.

But on Monday Cambodia's customs department confirmed it had halted exports.

"We have asked them (the company) to contact the Ministry of Health because the product comes from a human organ, so it needs permission from the Ministry of Health but they did not get it yet," Kun Nhem, General Director of Customs and Excise, told AFP.

He said government officials were planning to meet soon to "determine a policy about the product because it is a bit sensitive".

AFP visited the offices of Ambrosia Labs last week in Stung Meanchey, a poor suburb in the capital Phnom Penh.

The office, which uses the name Khun Meada, was shuttered. Local women who sold their milk said they had been told business operations had been suspended but they did not know why.

Chea Sam, a 30-year-old mother, said she had been selling her breast milk for the last three months following the birth of her son.

"I got my milk pumped six days per week and I earned between 30,000 to 40,000 riel ($7.5-$10) a day based on the quantity of our breast milk," she told AFP.

"I am poor, and selling breast milk helped me a lot," she added.

"We all cried when the company informed us about the suspension. We want it to be in business," she added, saying the knew of at least 20 other mothers who made money through their milk.

Cambodia remains one of Asia's poorest nations, with an average annual income per person of $1,160.

Ambrosia Labs did not respond to requests for comment.

But in an interview with a Cambodia-based reporter published on Vice.com last week, co-founder Bronzson Woods defended the business.

He said he hit upon the idea while working in the country as a Mormon missionary and that his company encouraged local women to continue breastfeeding and provide a steady income.

In a video uploaded to a YouTube account using the name Khun Meada, a western man identifying himself as the father of Bronzson Woods asked Cambodia to allow a resumption of exports.

"I'm confident that as the government here understands the good that this is doing that they will be on board," he said, adding the company had previously been allowed to export milk on six previous occasions.

Cambodia's Ministry of Health did not respond to requests for comment.