Libya has honoured a deadline to hand in a detailed plan on the destruction of its aging stockpile of mustard gas, left from the Kadhafi regime, the world's chemical weapons watchdog said Monday.

"We have received a detailed plan from Libya last week," Organisation for the Prohibition of Chemical Weapons' spokesman Michael Luhan told AFP, adding "it will now be reviewed by the OPCW's executive council".

The Hague-based OPCW, the implementing body of the Chemical Weapons Convention (CWC), in January gave Libya an end-of-April deadline to tell it how and by when Tripoli planned to destroy around 13 tonnes of sulfur mustard gas.

Libya's stockpile at Ruwagha, about 700 kilometres (430 miles) from the capital, consists mainly of artillery shells along with quantities of mustard gas and other chemicals declared by the Kadhafi government but not yet destroyed. Libya became on OPCW member state in 2004.

But the desert site also housed recently discovered stockpiles, brought there after the uprising in February last year that led to the overthrow and death of longtime leader Moamer Kadhafi some eight months later.

Luhan could not give the date pinned by the north African country for full destruction of chemical stockpiles, but said "it shouldn't take more than six months".

Canada last week donated 4.5 million euros ($5.9 million) to help speed up the process, while Iraq accepted a request from Libya earlier this month to help it tackle the chemical stockpile.

Libya has not yet started destroying the weapons as it had to be done under the eye of OPCW inspectors, Luhan said, pointing out the infrastructre to accommodate and insure the inspectors' safety on site were not yet in place.

Sulphuric mustard gas which burns and blisters the human skin was first used as a weapon during World War I, resulting in 90,000 deaths and over one million casualties, the OPCW's website said.

Later, during the Iran-Iraq war from 1979-88, Iraq used large quantities of chemical weapons. About 5,000 Iranian soldiers were reported to have been killed, 10 to 20 percent by mustard agent. Some 40,000 to 50,000 others were injured, the OPCW said.