A former Australian foreign minister says Cambodia's political leaders should be "named, shamed, investigated and sanctioned" by the international community over human rights abuses.
Gareth Evans, who was foreign minister from 1988 to 1996, has published an online article, titled Cambodia's Violent Peace, on his website, in which he says Cambodian citizens have been "deliberately targeted by their country's security forces".
"The recent killings repeat a pattern of political violence that recurred all too often at crucial moments in Cambodia's history," Mr Evans, who is now on the board of the Brussels-based International Crisis Group, said.
"Cambodia's record on democracy and human rights since the (1991) Paris Peace Agreements has not been a good one."
Mr Evans cites the shooting deaths of five garment workers in January, last year's deadly violence used against demonstrators protesting the 2013 election result, the 1997 grenade attack on an opposition rally led by opposition politician Sam Rainsy and prime minister Hun Sen's bloody coup in the same year as examples.
Mr Evans says "since then, while preserving a democratic facade, Hun Sen has ruled, for all practical purposes, as an autocrat".
"For far too long, Hun Sen and his colleagues have been getting away with violence, human-rights abuses, corruption, and media and electoral manipulation without serious internal or external challenge," he said.
Cambodia's leaders should be 'shamed, investigated' over violence
Mr Evans, who was foreign minister at the time of the UN peacekeeping operation in Cambodia and national elections in the early 1990s, says not enough is being done internationally to hold the Hun Sen government to account.
He says Australia's response to the violence has been "typical" and while it has expressed concern about "recent disproportionate violence against protesters", has failed to criticise the regime in Phnom Penh.
"Australia's new foreign minister, Julie Bishop, has talked, as foreign ministers often do, of the need to avoid unproductive 'megaphone diplomacy' and to 'engage, not enrage' her counterparts," he said.
"But, it seems that no robust critique was delivered when she met privately with Hun Sen in Phnom Penh on February 22 – even though Australia's high standing in Cambodia (not least owing to its historical role in the peace process) means that its voice certainly would have been listened to.
"I know Hun Sen and worked well with him in the past. I have resisted strong public criticism until now, because I thought there was hope for both him and his government.
"But their behaviour has now moved beyond the civilised pale. It is time for Cambodia's political leaders to be named, shamed, investigated, and sanctioned by the international community."
Human rights "on the right track"
The Cambodian government's spokesperson Phay Siphan told the ABC comments from Mr Evans "seem to be an over reaction".
"The situation has been improved... human rights is on the right track," he said, adding that compared to neighbours Vietnam and Thailand, "we feel that we are better".
Responding to violence used against demonstrators, Mr Phay Siphan says the authorities had to respond that way "to maintain peace and stability" and called Mr Evans to "respect the Cambodian people".
"If you compare Cambodia over here to other... ASEAN countries, I think that we are very open than the others," he said.
"Opposition party over here, international organisations over here, thousands of NGOs over here. (There is) freedom of expression through a number of radio stations and... people are free to express the political but we don't let those people take the law into their own hands.
"Human rights have to be taking place under the rule of law. It does not mean that the human rights have to be taking the law in everyone's hands."
Foreign Minister Julie Bishop has responded to Mr Evans, saying she raised human rights in her meetings with Cambodian leaders during her visit in February.
"I note Mr Evans has chosen to make these criticisms in the week following my visit to Cambodia, yet remained silent when Labor's Bob Carr visited Cambodia. I will not play politics with what is a serious issue," Ms Bishop told the ABC.
"I raised human rights in each of my meetings with the prime minister, deputy prime minister and foreign minister of Cambodia."