BEIJING - Hundreds of illegal golf courses have been built in China since a moratorium imposed to save farmland, and authorities are vowing harsh punishment for those responsible, state media said Tuesday.

Golf courses have mushroomed across China as the sport has boomed and a notice Tuesday from the land ministry said authorities had launched a survey as they seek to determine how many were built since the 2004 moratorium.

"We still don't know the exact figure. But we're working on it and will have the information by 2010. The culprits will face harsh punishment," the China Daily quoted Dang Zuoji, the ministry's director of land planning, as saying.

However, the report also said China, which saw its first golf course built in 1984, was expected to have 2,700 by 2015.

Recent state media reports have estimated current numbers at more than 500.

Maintaining sufficient farmland to feed China's huge 1.3 billion population has long been a concern of the nation's leaders, who have watched as rampant real estate development has eaten into land stocks.

Traditionally viewed as a rich man's sport in China, golf has enjoyed a boom in recent years thanks to rising incomes amid three decades of economic growth.

Little is expected to stop the juggernaut, especially with the decision in October to add golf to the programme for the 2016 Olympic Games.

The move is widely seen as resulting in a further push for the sport in China amid expectations the government will seek to dominate yet another Olympic event.