Titled "30 years of Hun Sen: Violence, Repression, and Corruption in Cambodia," and based on Cambodian documents, UN records and interviews with officials, journalists and NGOs, the Human Rights Watch (HRW) report chronicles Hun Sen's career from being a Khmer Rouge commander in the 1970s to his present role as prime minister and head of the ruling Cambodian People's Party (CPP).

The 67-page report, released on January 13 - almost three decades after Hun Sen took office as prime minister on January 14, 1985 - also accuses the PM's successive governments of violence, repression, and corruption, claiming the Cambodian politician has ruled through violence and fear.

Hun Sen is now the sixth-longest serving political leader in the world, just behind Robert Mugabe of Zimbabwe and ahead of Yoweri Museveni of Uganda. Sen, who has reportedly vowed to continue to rule Cambodia until he is 74, is regularly criticized by campaigners for ignoring human rights and stamping out dissent. But the 62-year old is also credited with transforming the country into one of the region's fastest-growing economies.

Nonetheless, a recent nationwide survey published by The Asia Foundation found that despite rapid economic growth, more Cambodians than at any time since 2004 feel their country is moving in the wrong direction, with corruption, deforestation, and economic issues topping the list of concerns.

In a DW interview, Phil Robertson, deputy Asia director of Human Rights Watch (HRW), talks about the report's findings and calls for a reform of key institutions such as the National Election Committee, the security fores, and the judiciary.

DW: How would you describe PM Hun Sen's 30-year rule of the country?

Phil Robertson: Hun Sen's 30 year rule has been marked by a totalitarian bent buttressed by serious human rights abuses, absolute control of power, and systematic persecution of opponents who dared challenge him.

Ruling Cambodian People's Party (CPP) cadres look to Hun Sen as their lodestone, the man who guarantees them wealth and power through land seizures, sweetheart government deals, and a propensity to look the other way when governing elites commit abuses against communities standing up for their rights.

What is particularly important is that Hun Sen's subversion of judicial independence in Cambodia, which has led to his complete control of the courts, and has significantly contributed to the impunity for rights abuses that he and his cronies, often well-connected members of the ruling CPP or the security forces, enjoy.

His machinations around Cambodia's every five year elections are particularly worrisome, with the latest election cycle showing how intimidation of opponents, combined with manufacturing of votes, were effectively combined with manipulation of election management machinery to steal an election.

In July last year, Cambodia's opposition agreed to drop a parliamentary boycott following talks with the prime minister, ending a year-long deadlock and easing political tension stemming from a disputed 2013 election. Doesn't this speak for Hun Sen's willingness to seek a compromise?

This so-called "compromise" was preceded by the arrests of a number of prominent opposition Cambodia National Rescue Party (CNRP) members on trumped up charges connected to efforts by the opposition to hold a public assembly in the so-called "Freedom Park" after weeks of systematic denial of their right to freedom of assembly.

Instigation of violence by security forces prompted retaliation by heretofore peaceful opposition demonstrators who decided they had finally had enough of government provocations. Such a reaction was not correct or proper, but it was used not to target those who committed violence but rather it was leaders of the opposition who were arrested as part of a CPP effort to get leverage over them in negotiations to form a parliament.

With Hun Sen, there is always a negative context to consider – and often there are actions connected with violence and intimidation that occur before a political deal is struck.

But Sen is also credited with transforming the country into one of the region's fastest-growing economies. What is your take on this?

Cambodia's economy so far has been a one-trick pony, with garment industry exports comprising the vast majority of the economic growth. Without the systematic corruption and land seizures by the CPP and its cronies, Cambodia's economy would be stronger and rural people would not have to send their daughters to work in garment production to survive.

You call for reforms in your report. What sort of reforms do you think are needed?

First and foremost, there needs to be a fundamental reform of the National Election Committee and other associated election mechanisms to make them truly independent so that Hun Sen cannot steal elections in the future. Ending his domination of the police, and the impunity to violate rights that such control allows, is critical.

Cambodia's CPP-controlled courts also need to be reformed with truly independent prosecutors and judges developed and put into office. Finally, there needs to be an end to the dual function of military and police, judges and prosecutors from being both civil servants and leading members of the CPP – that is a conflict of interest that should not be tolerated.

What do you urge the international community to do?

Cambodia is hugely dependent on the good will of donors to cover basic costs of programs. It is time that donors really use the leverage that they have to demand fundamental reforms, and not just cosmetic changes.

A campaign of continuous monitoring and pressure is what is needed to demand a change in the way that Cambodia operates, and strategic ideas for reform need to be developed and pressed on through to fruition.

Where do you see Cambodia in the coming years?

Sadly more of the same unless Hun Sen's influence is effectively countered by reforms and efforts to embed respect for human rights in the political culture.

Phil Robertson is deputy Asia director of Human Rights Watch.