On a hot May afternoon, Cambodian sister and brother Hut Heap and Hut Hoeub left their makeshift family home to search for fresh water.

They never returned. Hours later, the bodies of the 13-year-old girl and her nine-year-old brother were found at the bottom of an eight-metre-deep pond by men prodding the water with poles.

It had been just four days since the siblings, their family and 50 others had been uprooted from their homes and moved to a resettlement site to allow work to begin on a rail project partly financed by the Australian government and operated by the Melbourne firm Toll Holdings and its partner, Cambodia’s Royal Group of Companies.

Pay Lin, the elder brother of the drowned siblings, said they went to the pond because there was no fresh running water at the resettlement site for washing dishes, cleaning clothes or bathing.

”They went to play in the water … The younger one drown first. The bigger one went to help, but can’t help. The water is too deep,” he told representatives of the aid group Bridges Across Borders Cambodia.

Months later, there is still no fresh piped water and people have to draw water from the pond or an adjacent rice field polluted by chemicals that burn skin.

”If there were people coming to install water and electricity before I moved to live here, my siblings would not die,” Lin, 25, said. ”Because there is no water, that’s why my siblings came here [to the pond] to get fresh water for dishwashing.”

David Pred, the executive director of Bridges Across Borders Cambodia, and an Australian human rights lawyer, Dr Natalie Bugalski, said the resettlement site also did not have affordable electricity and was further removed from places of work, forcing already poor families to borrow money to survive.

The deaths of Hut Heap and Hut Hoeub raise awkward questions for the Australian government aid agency AusAID, which contributed $21.5 million to the rail network, and Toll Holdings, whose Cambodian joint venture with the controversial tycoon Kith Meng has a 30-year contract to build and run the network.

Pred and Bugalski want to know what measures AusAID, the Asian Development Bank – the project’s financial supporter – and the Toll joint venture took to ensure the families would have access to basic services and livelihood opportunities.

They want to know why families forced to leave their homes have in some cases been given $200 in compensation.

Pred and Bugalski believe the Australian government has a moral and legal obligation to ensure those affected by development projects it funds are afforded the essentials of life.

”The often disastrous displacement impacts of infrastructure projects are well known,” Bugalski said.

”AusAID is being negligent in failing to ensure that Australian aid is not being used in a way that harms poor families in developing countries.”

Pred said AusAID should have conducted a human rights impact assessment before funding the railway rehabilitation project, which will displace thousands of people.

AusAID was informed by Bugalski and others on October 4 of the deaths of the children and of concerns about conditions at the resettlement site.

After waiting for a reply for more than two weeks – but not receiving one – a coalition of non-government organisations wrote to AusAID’s deputy director general, Richard Moore, on October 21 telling him of the deaths and urging him to conduct an investigation and compensate their family. An AusAID spokeswoman said the Cambodian government was responsible for the site.

She said an AusAID-funded adviser was monitoring the resettlement and concerns had been raised with Cambodian authorities since July.

”Electricity has now been connected to the site and the Cambodian government is working to provide adequate access to water as soon as possible,” she said.

Asked about the drownings, the spokeswoman said any investigation was a matter for the Cambodian government.

Toll Group said also that questions should be referred to the Cambodian government and the Asian Development Bank.

”It’s not part of our responsibility under the concession,” a spokesman said.

The controversy over the Battambang resettlement site is not the first in Cambodia involving the Australian government or Toll’s joint venture partner, entrepreneur Kith Meng.

In June last year, Australian diplomats moved into a new embassy in Phnom Penh on a plot of land the government bought from Meng for $15 million.

Two weeks later, armed police surrounded land next to the embassy and evicted several poor families who had lived there for years.

As the evictions were taking place, the embassy signed a petition calling on the Cambodian government to stop the forced removal of people from areas of disputed land, prompting accusations of hypocrisy from human rights groups.

Meng’s Royal Group of Companies has previously been associated with controversial forced evictions where police and armed forces have herded families from land earmarked for development.

Bugalski said she hoped the deaths of Hut Heap and Hut Hoeub would not be in vain and that the Australian government would improve the situation for affected families.

As for Lin, he simply wants help for the families at the Battambang site. ”I want the government to help our people. We are very poor and now two of my siblings died from drowning … Please help us by providing jobs. I want a job.”