General Motors (GM), the world's No. 1 automaker, has announced the head of its China office will step down for "personal reasons".

Phil Murtaugh, chairman and chief executive officer of GM China since 2000, "will leave the company for personal reasons," the China Daily newspaper reported on Thursday, citing a spokeswoman from GM China Group.

Although details of the 50-year-old Murtaugh's departure are yet to be known, GM's sales drop in China so far this year is seen by some as the main reason.

Sales of China-made vehicles dropped by 6.94 percent year-on-year to 684,500 units in the first two months of this year, industry statistics showed.

However, Troy Clarke, vice-president of GM Group and president of GM Asia Pacific, praised the departing CEO for "playing a key role in GM's aggressive China growth strategy."

"Our Chinese partnerships are strong. Our China operations are doing well. Under Phil's leadership, GM has achieved record sales approaching nearly 500,000 units a year and become an industry leader with more than 9 per cent of the vehicle market," he said in a statement.

"Our China sales are on track for double-digit growth once again this year," the statement said.

The figure maintained GM as the second biggest automaker in China after Volkswagen, which sold almost 650,000 vehicles in the nation last year, down 7 per cent from 2003.

GM runs four joint ventures in China with Shanghai Automotive Industry Corp. (SAIC), one of China's biggest automakers to produce Buick, Chevrolet and Cadillac cars.

Like GM, many automakers have also seen sales decline this year and the whole auto market is at a low ebb, analysts said.

In order to boost sales performance, GM said in January it planned to introduce a record number of all-new or upgraded vehicles in China this year.

It also announced last year to invest a further three billion dollars jointly with SAIC into the joint ventures and double its annual production capacity in the country to 1.3 million units by 2007.