The manufacturer of plastic car accessories drew back the curtain on Tuesday on its new portable toilet for cars.

The toilet comes with a curtain large enough to conceal users and a plastic bag to collect waste.

"The commode will come in handy during major disasters such as earthquakes or when you are caught in a traffic jam," a company official told reporters, according to Kyodo News.

Japan is situated on the Pacific "Ring of Fire" and accounts for about 20 percent of the world's earthquakes of magnitude 6 or greater.

Drivers stranded by tectonic movements or stuck in tailbacks simply assemble the cardboard toilet bowl, fit a water-absorbent sheet inside and draw round the curtain.

The product is small enough to fit inside a suitcase, the company said.

But prospective customers will have to hang on until November 15, when the firm begins selling the new product online.