BEIJING (AP) -- Several PC makers were including controversial Internet-filtering software with computers shipped in China on Thursday despite a government decision to postpone its plan to make such a step mandatory.

Beijing's decision this week to delay the requirement that the filtering software -- known as Green Dam -- be pre-installed or supplied on disk with all computers sold in China averted a possible trade clash with the United States and Europe. But the move by some makers to include the software anyway could re-ignite complaints by Chinese Web users.

Also Thursday, a government newspaper said regulators will revive the plan to make Green Dam mandatory at some point, a move that would disappoint opponents who hoped the government would drop the effort.

Taiwan's Acer Inc. -- the world's No. 3 PC maker -- Sony Corp. and China's Haier Group said they were shipping Green Dam on disks with computers for sale in China. China's Lenovo Group, the No. 4 producer, said it would offer the software pre-installed or on disk. Taiwan's Asus Inc. said it was preparing to supply Green Dam disks with PCs. Taiwanese laptop maker BenQ Inc. said the system was on the hard drives of its computers.

Acer was supplying Green Dam because disks were already packed with PCs before the government postponed the plan, that had been due to take effect Wednesday, said a company spokeswoman, Meng Lei. Lenovo said it also was going ahead with plans made before the Green Dam order was postponed.

Hewlett-Packard Co., the world's top PC manufacturer, said it was working with the U.S. government to get more information and declined to comment further. No. 2 Dell Inc. said it was not including Green Dam with its PCs.

Chinese authorities said the software is needed to shield children from violent and obscene material online. But experts who examined it said Green Dam also would block material the government deemed politically unacceptable.

Sony said it does not know how long it will continue to supply the software.

"What we will do in the future is still undecided because it will depend on the situation," said Sony spokesman Shinichi Tobe.

A Toshiba Corp. spokeswoman, Yuko Sugahara, said the company was deciding how to proceed.

An official of the Ministry of Industry and Information Technology quoted Thursday by the China Daily said regulators will revive the plan to make Green Dam mandatory.

"The government will definitely carry on the directive on Green Dam. It's just a matter of time," the unidentified official was quoted as saying.

Beijing operates extensive Internet filters to block access to material considered obscene or subversive. Still, Chinese Web users were outraged by Green Dam, which would have raised screening to a new level by putting it on each computer.

The controversy was sensitive for global computer makers, for which China is both a major market and the production site for up to 80 percent of the world's PCs.

Washington and the EU have complained that the Green Dam order, imposed abruptly in May, might violate China's free-trade pledges because manufacturers got too little notice and no time to comment. Producers had little time to test the software, made by an obscure Chinese company, and industry groups warned it might cause security problems.

American diplomats have been talking with Chinese officials about the plan. The U.S. Embassy in Beijing said Thursday it had no information on the status of talks. European Union officials have also objected to the plan.

Green Dam already is in use in Chinese Internet cafes and manufacturers say it has been supplied since early this year with PCs sold under a government program to subsidize appliance purchases in the poor countryside.

Associated Press researcher Bonnie Cao in Beijing and AP Business Writer Yuri Kageyama in Tokyo contributed to this report.