The United States has announced it will not issue visas to Cambodian officials it says are undermining democracy in the kingdom, and is calling on Prime Minister Hun Sen's Government to reinstate the country's political opposition.
Hun Sen, who has ruled Cambodia for 32 years, will effectively run unopposed in elections next year following the dissolution of Cambodia's main opposition party and the arrest of its leader, Kem Sokha.
His government's wide-ranging crackdown has led to the closure of independent media outlets, while threats have also been made against an opposition-linked human rights organisation.
The US State Department said the visa bans on certain individuals were in direct response to the ruling party's attacks on political freedom. The restrictions may also apply to family members of officials.
In a statement, the department called on Cambodia to release Mr Sokha, overturn the ban on his party and allow media and civil society groups to operate freely.
"The United States is taking concrete steps to respond to the Cambodian Government's actions that have undermined the country's progress in advancing democracy and respect for human rights," it said.
"The Secretary of State will restrict entry into the United States of those individuals involved in undermining democracy in Cambodia."
Hun Sen previously challenged the US to cut all aid funding to Cambodia, after it announced last month it would no longer fund Cambodia's upcoming election.
Australia urged to impose 'targeted sanctions'
While Australia has expressed concern about the situation in Cambodia, unlike the US it has not made any attempt to pressure Hun Sen's Government.
Australia has also said it would continue to pursue the option of resettling refugees on Nauru in Cambodia despite the decline of political rights there.
Exiled Cambodian opposition politician Mu Sochua, a senior leader of Mr Sokha's now-dissolved Cambodia National Rescue Party, called on Australia to sanction Cambodia's Government.
Mu Sochua is visiting Australia and met with Foreign Minister Julie Bishop on Tuesday.
"Expressing concern is not enough because these concerns have been expressed over 25 years," she told PM.
"We are calling for targeted sanctions, which means not issuing visas to high-ranking officials, no scholarships for soldiers coming from Cambodia to Australia, we are calling for the freezing of assets of high-ranking officials coming to Australia."
Mu Sochua said there were high-ranking Cambodian officials with investments in Australia, which she said were purchased with ill-gotten gains.
"We know there are quite a few [officials] who are investing in Australia in real estate and their money is — we suspect and we have evidence — linked to corruption," she said.
"They have mansions, they have villas in Sydney, in Melbourne. They drive their cars around Melbourne and Sydney that are worth hundreds of thousands of dollars.
"And if we compare to the jobs and the titles and positions that they have, they cannot afford these cars."