SHANGHAI - China's air cargo watchdog has extended a nationwide overhaul of safety among the courier sector and plans to kick inferior players out of the game.

At an industry workshop held on Wednesday in Shanghai, the China Air Transport Association announced that the nationwide safety overhaul, which began on Nov 23, will last until April 30, instead of January 23 as originally planned.

The overhaul was ordered after flammable materials carried by a courier firm caused a fire on a China Southern airplane in October. Four courier companies including influential Shanghai YTO and Yunda Express were ordered to suspend airfreight services until their business procedures improve.

Couriers have been key to the boom of e-commerce in China over the past few years. But safety problems also pop up as companies rush into the logistics sector to take a share of the huge market.

Duan Kaihong, deputy secretary of the CATA, said the association plans to set up a credibility system to track courier firms' safety records.

The association is also mulling measures to raise the sector's standards to exclude incompetent players, he added.