The Czech Republic's environment ministry said Monday it was planning to impose a moratorium on shale gas exploration that would ban new research projects for up to two years.

"My ambition is to draft a law setting clear rules of the game -- something the current legislation does not do," Minister Tomas Chalupa said on the ministry's website.

"I wouldn't want to find myself in a situation wherein a private company will sue the Czech Republic in arbitration over lost profits only because Czech laws were not good enough," he added.

The ministry in April rejected a bid from BasGas Energia Czech, a unit of the international group Hutton Energy, to start research in the north of the country.

A similar request from Britain's Cuadrilla Resources is pending a decision.

The ministry's plan follows protests and petitions from several regions anxious that exploratory shale gas drilling might damage the quality of drinking water.

Shale gas drilling is based on hydraulic fracturing or 'fracking', a technique using high pressure injections of water, sand and chemicals to crack open rock and release oil and gas trapped inside.

Fracking has been banned by countries such as France and Bulgaria, while Romania said last week it would seek a moratorium too.

In contrast, Britain, parts of the United States and Poland have stood up in favour of the technology.