HONG KONG - Maersk Line, the container division for the Copenhagen-based shipping conglomerate AP-Moller Maersk Group, plans to increase freight rates to restore its business' ability to make profits, said Tim Smith, chief executive for the company in North Asia.

"The current freight rates are too low," Smith said at a news conference in Hong Kong. "They are not sustainable."

Yet economists and analysts said the increased shipping charges might further hinder the already weak growth in China's exports.

The shipping industry has had a tough year in 2011, a time when more than two-thirds of shipping companies in the world reported financial losses, industry data showed.

Maersk Line, the world's largest container carrier by capacity, reported an annual loss of $600 million in 2011. In the previous year, it had enjoyed a profit of $2.6 billion, according to a company financial statement released on Monday.

The negative results were mainly caused by low rates charged for shipping container freight between Asia and Europe, the company said.

Since the beginning of this year, the company has twice proposed raising the rates. In January, Maersk announced plans to increase shipping costs by $775 for every container that goes out on a westbound route starting on March 1. A few weeks later, the company said it would raise the costs by an additional $400 in April.

If both rate increases are put into effect, they will tack $1,175 onto the price of shipping a container from all Asian ports and going to places in north Europe and the Mediterranean, the company said.

The rate increases will also more than double the current freight rates, but even that was still far below the price peak in 2010.

Maersk said it has received positive responses from customers and was optimistic that the market will accept the increases. For exporters, "the proportion of shipping costs is still very low and our rate increases are affordable", Smith said.

Following Maersk's announcements, nearly every large carrier involved in trade between Asia and Europe decided to increase the cost of shipping a container by about $750 to $800 starting on March 1.

Among those that took the step were China's main shipping conglomerates, including China Ocean Shipping (Group) Co and China Shipping (Group) Co. It remains unclear, though, whether they would follow Maersk in adopting a second increase or, in an attempt to boost their market shares, stick with the one that is to take effect in March.

Last week, the freight rates charged on the route between Asia and Europe increased to about $800 for every container after falling below $500 in late 2011, according to the Shanghai Containerized Freight Index. The index was established by the Shanghai Shipping Exchange to reflect spot rates on the Shanghai transport market for export containers.

The shipping industry's decisions have prompted concerns that the rate increases might be passed onto Chinese exporters and squeeze their profits.

"Increased shipping costs will affect the furniture manufacturing industry," Hou Kepeng, secretary-general of the Shenzhen Furniture Trade Association, told local media.

More than 100 furniture manufacturers now operate in Shenzhen, and most of their exports go to Europe and the United States.

Recent months have been rocky for China's exporters. The country's exports to rich countries were expected to stall in the coming months, not least because the "sluggish economic recovery and debt crisis in the United States and the European Union will further dent consumer demand", Zhang Monan, an economist at the Economic Forecast Department of the State Information Center, said in a recent interview.

In January, the value of China's trade declined by 7.8 percent from a year before, hitting $273 billion. Exports fell by 0.5 percent from the same period last year, decreasing to $150 billion, and imports slid by 15.3 percent, hitting $123 billion, according to the Ministry of Commerce.