The new commercial centre would include high rises and a major dredging operation stretching from Phnom Penh to Vietnam.

CAMBODIA's largest-ever property and industrial complex is expected to get under way, according to David Chanaiwa, chairman of Brothers Investment Group, which is behind the development.

The massive US$1.6 billion project would include a deep-water port on the Mekong River, a 60-storey residential high rise, a marina and a digital media centre.

Most ambitious is the company's plan to dredge the Mekong from Phnom Penh to the Vietnamese border to allow heavy cargo ships to travel year round.

"The project will reduce cargo costs ... a lot of traffic will be redirected from roads to the Mekong," Chanaiwa said.

He said that the initiative is backed by Korean and Japanese investors, but would not specify their names.

Chanaiwa's company has been in business for one year, and he would not reveal its other investments, only saying it is backing the Royal De Castle building.

He said the company has received approval from the ministries of public works and water resources to commence dredging, starting near Phnom Penh, but that the government had not agreed to reinforce the riverbank.

"The government needs to act now to protect the riverbank from erosion," Chanaiwa said.

He added that he has urged the government to spend $300 million to $500 million on an embankment to protect the shoreline from erosion.

The mini-city would be built on reclaimed land from the river, said Chanaiwa, emphasising that local residents would not be forcefully evicted from the site.

But environmentalists caution that dredging could be detrimental to the Mekong.

"The Mekong is a very sensitive ecosystem - dredging the bottom would seriously affect the fish migration routes," said Bunra Seng, country director for Conservation International.

One key business leader said that he had heard nothing of the proposed project and that he doubted its credibility.