Cambodia is aiming for the record books with an ambitious plan to construct Asia's tallest building, a 555-metre skyscraper worth $200 million, Prime Minister Hun Sen said on Wednesday.

The building would be five times taller than the country's present highest structure, the new, 32-storey Canadia Bank Tower, which dominates the Phnom Penh skyline, where buildings of more than five floors stand out.

If the project goes ahead, it would top the Taipei 101 Tower, the Shanghai World Financial Center and Kuala Lumpur's Petronas Towers -- the world's three tallest buildings after the 828-metre Burj Khalifa in Dubai.

"It will be shorter than the one in Dubai and taller than any buildings in Asia, and I think we can do it," Hun Sen announced during a university graduation ceremony on Wednesday.

"We don't have to be too conservative and we also don't need to be too outdated," Hun Sen added, brushing off criticism from cultural groups concerned that a construction boom was threatening the city's French colonial architecture.

Hun Sen said the proposal had been made to the country's Land Management Ministry and local lender Canadia Bank would be involved in the project.

However, real estate companies questioned whether there was much demand for a building half a kilometre high in the capital of one of Asia's poorest countries.

"Where would the investors come from?" said Sung Bonna, CEO of Bonna Real Estate Group in Phnom Penh.

"We are concerned about the shortage of demand and occupancy rates so we need time, but we hope this dream comes true."