BEIJING, July 17 -- "Official vehicle reform" became the hottest topic on China's portal websites and social media on Wednesday, with millions commenting on an official car use directive barely an hour after the decision was published.

A directive jointly released by the Communist Party of China and the State Council Wednesday on reforming the use of official cars has sparked strong and mixed reactions from netizens.

By the end of the year, central government officials of all ranks below deputy minister will be banned from using official vehicles, except for special services such as emergencies and law enforcement.

Unused cars will go to public auction, with all the cash turned over to the state treasury. Drivers and other staff who may be affected by the change will have to be "properly relocated."

The move has generally been met with applause from the public, who view it as a reflection of the Party and government's determination to curb graft and rein in extravagant spending by officials.

"Finally, the central authorities are starting to root out the corruption on wheels. Good job," read a post on web portal Sina by a netizen named "a responsible Chinese."

"So long as the central authorities get tough and the central government takes the lead, there is no reform that cannot be carried out," said a netizen named Yongren on Sina.

Previous attempts by the central government dating back 20 years to cut down on the number of official cars have failed, as the reforms were not detailed or pragmatic enough to be implemented.

"Finally, there are signs of real progress about official car reform after 20 years of talking and talking," said Baiyang1514 on the website.

However, some have reacted cautiously, arguing the new policy will be hard to implement or could be "distorted" to bring extra "benefits" to officials.

"As it will take years to really implement the reform, I hope the authorities do not give up halfway, but forcefully push forward the reform," said Baiyang1514.

Under the reform, the officials will be given transport subsidies ranging from 500 yuan to 1,300 yuan a month instead.

"Hope it will not end in officials having both the cars and the subsidies," commented a user on the social media platform Weibo.

An unnamed official on Sina pointed to previous similar reforms in state-owned enterprises (SOEs) that resulted in higher income for medium and high-level officials as a caution that the reform could go astray.

To prevent official cars from being used for private purposes, many netizens called upon the authorities to clearly mark all official cars with red number plates or other obvious signs so that the public can monitor their use and allow greater oversight.

The authorities promised to finish reform in central government organs by 2014 and in local governments by the end of 2015 to accomplish comprehensive reform in two to three years, according to the guideline.