Taiwan tech giant Foxconn said Tuesday all its workshops that polish electronic parts and products in China had been shut down for inspection after a deadly explosion at a plant last week.

The firm said three workers died and 15 others were hurt in Friday's explosion at the Hongfujin Precision Electronics workshop in southwest China, which assembles Apple's popular iPad 2.

The news led analysts to warn that production of the tablet could be slashed by half a million if the stoppage goes on for too long.

"The cause of this tragic accident is still being investigated by a joint investigation task force led by government officials and law enforcement authorities," spokesman Edmund Ding said in the statement.

He added that "all operations at the affected workshop remain suspended and production at all other workshops that carry out similar processing functions have also been halted pending the results of the investigation".

Initial findings showed that the accident may have been caused by an explosion of combustible dust in a duct, he said.

Research firm IHS ISuppli said with monthly production of iPad 2 at the plant in Chengdu, southwest China, amounting to 500,000 units, a shutdown until the end of June would seriously impact output, according to Dow Jones Newswires.

Shares in Hon Hai Precision, the parent company of Foxconn, fell 2.91 percent Monday but rebounded 3.0 percent Tuesday.

"The unexpected accident's negative impacts on the operation of Foxconn should be limited," Kuo Ming-chi of the Concord Securities told AFP.

He added that up to 70 percent of iPads are manufactured at Foxconn's plants in southern China.

It is the latest incident to hit embattled Foxconn, after at least 13 of its employees died in apparent suicides last year, which activists blamed on tough working conditions.

Foxconn employs about one million workers in China, about half of them based in its main facility in the southern city of Shenzhen.

Foxconn has been expanding its workforce in other parts of China as it seeks to scale back the size of its Shenzhen plant.

The firm opened the $2 billion Chengdu plant in October, according to China's state-run Xinhua news agency.