Turkey on Tuesday launched construction of its first nuclear power plant which Ankara hopes will open a new era of greater energy self-sufficiency, but the ceremony was marred by angry protests against the controversial $20 billion project.

After the launch ceremony, dozens of environmental protesters converged on the iron gates of the site in Akkuyu in Mersin province on the shores of the Mediterranean.

They managed to lock in the official delegations, security forces and journalists inside the site and were only dispersed when a water cannon truck was used against them, video footage showed.

The power station -- which will have four power units with a capacity of 1200 MW each -- is being built like Iran's first nuclear power plant by Russia's nuclear agency Rosatom.

"Development cannot happen in a country without nuclear energy," said Turkish Energy Minister Taner Yildiz at a ceremony attended by the head of Rosatom, Sergei Kiriyenko and other top officials.

Yildiz vehemently rejected that Turkey was entering the nuclear power sector at the wrong time after the Fukushima nuclear disaster in Japan in 2011 and with Germany phasing out its nuclear power.

"All sectors (of the industry) have learned lessons from Fukushima. Akkuyu power station has also learned lessons," he said.

Yildiz said that the power station would pose no threat to tourism on Turkey's sun-drenched Mediterranean coast, saying the use of nuclear power in Spain and France had not harmed tourism there.

The authorities have gone on a publicity offensive to promote the plant, with television commercials and billboards showing happy children running and cycling in a bucolic landscape under the shadow of the power station.

"Akkuyu nuclear power station: a new energy for a powerful Turkey," said a full page advertisement in Tuesday's newspapers.

- 'Turkey not ready' -

Akkuyu is the first of three nuclear power plants Turkey currently plans to build to reduce its dependence on importing energy from oil and gas exporters like Russia and Iran.

A second plant is due to be built by a French-Japanese consortium in the Black Sea city of Sinop while a third plant whose location is yet to be finalised is also envisaged.

"If we had built this power station 10 years ago, we would have saved $14 billion in natural gas purchases," said Yildiz.

Yildiz and Kiriyenko were to lay the foundation stone for the construction of the power station, which is expected to be completed by 2020.

The Turkish authorities have swatted away concerns that the Akkuyu facility lies in a seismic zone, saying it can resist quakes registering up to nine on the Richter scale.

However the Akkuyu plant has become a bete noire for environmentalists who have raised alarm about safety issues and the building of the power station in an area rich in wildlife.

Environmental campaign group Greenpeace in January lodged a complaint in court against the awarding of an environmental impact licence to the plant and says it should not be built.

"Turkey is not ready to build nuclear reactors -- the country is still missing the key pieces of necessary legislation," Jan Beranek, the director of Greenpeace Mediterranean, told AFP.

He said that the seismic assessment had been "totally inadequate" and accused the authorities of ignoring issues related to radioactive spent fuel which risked being transported through Istanbul on the Bosphorus Strait.

"There is no need for the country to set on a path of unpredictable nuclear hazards and this outdated, yet very expensive technology," he added.

As well as in Akkuyu, dozens of people also protested in Istanbul and Ankara.

The launch of the power plant comes two weeks after Turkey suffered its most serious nationwide power cut in 16 years which exposed the shortcomings of its energy system.

The project is strongly backed by President Recep Tayyip Erdogan as part of his plan to make Turkey one of the world's top ten economies.