Vietnam's prime minister has approved a plan to sell a majority stake in brewer Sabeco, a government committee said in a document seen by Reuters on Tuesday, taking the state-controlled brewer one step closer to a long-awaited sale.

Vietnam has one of the world's most attractive beer markets and the biggest in Southeast Asia, thanks to a young population that consumed nearly 4 billion litres in 2016.

Foreign brewers from Kirin to Heineken have been looking at a possible investment in the maker of the Bia Saigon and 333 brews since it was earmarked for privatisation. But long-stated plans for the government, which still owns about 90 percent, to sell a majority stake have met with repeated delays.

A meteoric rise in Sabeco's share price due to high demand and a small float has complicated matters, making it difficult for industry buyers - including Heineken which already owns a 5 percent share - or other investors to step in.

The stock listed at 110,000 dong but is now trading at around 255,000 dong, a more than 130 percent increase.

The document did not mention a timeline for the sale or how much the government wants to raise.

Sabeco, the country's second-biggest listed firm by market value, is a key plank of a broader privatisation effort, which includes dairy firm Vinamilk, Vietnam Airlines and rival brewer Habeco.

The Vietnamese government also plans to sell a further sliver of Vinamilk, around 3 percent, at 154,000 dong each, higher than the previous estimate, according to a government document seen by Reuters on Tuesday.

The divestment out of Vinamilk, Vietnam's top firm by value, is expected to bring in 7.443 trillion dong (US$328 million) to the state, Vietnam's Steering Committee for Enterprise Innovation and Development said in a statement dated Aug 30.

The State Capital Investment Corp, the government's representative in Vinamilk, said it estimated the stake sale would fetch 6.5-7 trillion dong.