Imagine contraception was as easy as flipping a switch. Well, now a German inventor says it is.

Former carpenter Clemens Bimek says he's perfected a device which, once implanted under a man's skin, can turn the flow of sperm on and off.

Philipp Renger is in charge of marketing the Bimek SLV.

Clemens Bimek is the inventor of the Bimek SLV. (Bimek SLV)

He tells As It Happens guest host Helen Mann, "A man will have it in his scrotum. It basically looks like a light switch."

Renger explains that a man using the device would normally keep it in the 'on' position, which would be similar to having a temporary vasectomy. If he wanted to conceive, it would be switched 'off', allowing sperm to enter a man's ejaculate.

He says it can take a number of weeks after being switched 'on' before a man can be sure that there is no longer any sperm present when he has sex.

The company released a picture illustrating how the devices are installed between a man's severed sperm ducts.

(BIMIK SLV)

In 2008, Bimek had a prototype of his invention implanted into his own scrotum. Bimek insisted on remaining awake during the procedure so he could help guide the surgeon.

It didn't go as planned.

"When it was implanted he found that it was difficult to open and close it," says Philipp Renger. "That didn't work very well."

Renger says subsequent redesigns, and more surgeries for Bimek, have resulted in a working sperm switch.

"It sounds terrible...but it worked really well," says Renger.

Now the company just needs a few dozen men who are willing to try the invention. The company hopes to release the final product sometime in 2018.