French energy group Total is to hand back one of its two shale gas licences in Denmark after disappointing test drilling results, the Danish Energy Agency said on Friday.

"They have told us that they will return the licence," agency spokesman Ture Falbe-Hansen told AFP.

The North Zealand shale gas project had been controversial and local politicians tried to ban the so-called fracking process to extract the gas amid fears that ground water could be contaminated by drilling fluids.

Total said the decision to hand back the licence was purely due to poor results from test drilling in the area.

"The reason is that our studies have shown that the shale layers turned out to be very thin in North Zealand," project coordinator Henrik Nicolaisen told Danish daily Politiken.

The Danish Minister of Climate and Energy, Rasmus Helveg Petersen -- whose Social Liberal Party is opposed to fracking -- said in April that he won't renew or issue any more permits for onshore shale gas exploration.

Earlier this month Danish authorities stopped exploratory drilling at Total's other shale gas project in the country, in Vendsyssel in the far north, after the French company used an unauthorised chemical.

Total said it expected drilling to resume later this week.

Fracking or hydraulic fracturing is a process used to extract gas or oil from shale rock by blasting a high-pressure mixture of water, sand and chemicals deep underground to release hydrocarbons trapped between layers of the rock.