Korean games firm NCSoft will cut staff in the US after a costly new online game fell far short of revenue targets, according to an executive quoted in local media reports.

Tabula Rasa, which was developed in Austin, Texas, generated revenues of just $5.4m in the fourth quarter, following its launch at the beginning of November.

Development of the game has cost approximately $100m over the past five years, the Korea Times reported, without naming sources.

"Because of this disappointing result, some downsizing in Austin is inevitable,'' Lee Jaeho, chief financial officer at NCSoft, told analysts.

"Half a year ago, I communicated to investors and analysts that we have very high expectations for Tabula Rasa. But after just six months, I have put down $15.8m as our annual revenue target, and that is very disappointing."

Lee acknowledged that, when development costs are taken into account, NCSoft is probably not making a profit from Tabula Rasa.

The game was formally launched in November 2007 to reviews that were mostly positive, but not outstanding.

Tabula Rasa was developed by a 300-strong team led by noted games designer Richard Garriott, who created the successful Ultima Online.

The firm is looking to Garriott to help rescue Tabula Rasa with improvements, a spokesperson told Korean media. However, he is currently in Russia undergoing training for a $30m October 2008 flight to the International Space Station.

NCSoft reported net profit of $48.4m on sales of $355m for 2007. The company was founded on the tremendous success of the Lineage series in Asia which still accounts for more than 75 per cent of sales.

NCSoft also publishes the popular US-developed online games Guild Wars and City of Heroes.