On Four Corners on Monday night, Sophie McNeill reports how Australia is accused of failing to stand up for democracy in Cambodia, as it descends into dictatorship.

"You don't drink champagne with the dictators." Opposition Leader

For more than three decades Cambodia has been ruled by one man, Prime Minister Hun Sen, who came to power in the country's first democratic elections after the horror years of the Khmer Rouge. Australia played a key role in the peace deal that ended the bloody civil war, but the once bright hopes for democracy have long since faded.

"We were tremendously successful in bringing peace to Cambodia, but we weren't at all successful in bringing democracy and human rights." Former Australian Foreign Minister Gareth Evans

Ahead of this weekend's elections, the Hun Sen regime launched a ruthless crackdown on the political opposition and free press. On Monday, in her first story for Four Corners, reporter Sophie McNeill travels to Cambodia to confront the man whose political opponents have been imprisoned and assassinated in mysterious circumstances.

Sophie McNeil: The world says this is not a democracy…

Hun Sen: No, no, no. No this is not (right).

While steadily cementing their grip on power, Hun Sen and his family and cronies are accused of amassing enormous wealth through a corrupt and nepotistic system.

"There's nothing that happens there that they don't control, and that is corruption in its most egregious form. That's what it's like in Cambodia. It is a Mafia state." Patrick Alley, Director Global Witness

Four Corners has uncovered evidence of how the regime's wealth has been used to buy properties and businesses in Australia, where some of Hun Sen's relatives have established a base for building support, sometimes through threats and intimidation.

"They allow this foreign government to intimidate our people, Australian citizens, and those who come here to study. This is not right." Hong Lim, Victorian MP

Since 2014, Australia has granted the regime $40 million in additional aid, in return for taking some of Australia's unwanted refugees, and the Turnbull government upgraded ties with Cambodia last year. While the US has begun moves to sanction the regime by freezing assets and blocking visas, international observers accuse the Australian government of cosying up to Hun Sen.

"I would like to see Australia take a strong stance, (to) come out openly and condemn the Hun Sen regime. They're not doing that." US Congressman

While hopes for democracy have disintegrated, China has moved to dramatically expand its presence and power in the country.

"Cambodia has the coast, Cambodia has minerals, Cambodia has forest, Cambodia has a dictator. You can buy it all." Opposition Leader

As Hun Sen prepares to tighten his grip on power after this weekend's elections, Cambodia's democracy campaigners say they feel abandoned.

"Cambodia look up at the people of Australia. We envy you. You live in a world of democracy, but your government is disappointing. Very disappointing." Opposition Leader

哇，窗口太小啦

Four Corners