A French labour union said members working in the energy sector had on Thursday cut power to the building sites for the Olympic Village for the 2024 Paris Games, as well as the main Stade de France stadium.

Gas and electricity supplies were cut to the sites as well as data centres, said Sebastien Menesplier, secretary general of the hardline CGT union's energy branch, as unions step up actions to thwart the government's controversial pension reform.

Unions are keeping up actions to force the government to drop the plan, with transport and other public services disrupted in France for the third day in a row.

The government under President Emmanuel Macron says raising the retirement age from 62 to 64 and stiffening the requirements for a full pension are essential to keep the system from sinking into deficit.

"Faced with a government that refuses to budge, we too are refusing to budge," said Menesplier.

"I appeal to the responsibility of the government and the president of the republic: withdraw your reform and the electricians and the gas workers will work for the public service and the general interest", he added.

About three hundred employees were present for the action which saw them tamper with four key cables. Some, hooded, raised their arms and lit smoke bombs to hide those who cut the power from the cameras.

The electricity supplier then sought to work rapidly remotely to restore supplies to the affected areas.

- 'Serious democratic problem' -
 

Strikers in the energy sector have since Tuesday staged wildcat power cuts, plunging certain sites across the country into darkness.

Government spokesman Olivier Veran on Wednesday condemned the wildcat cuts while expressing respect for the right to express disagreement in the street.

"We condemn calls to bring our economy to its knees because this is irresponsible. The only thing we want to bring to its knees is unemployment," he added.

The government late on Wednesday passed a major legislative hurdle for its bill when the upper house Senate, dominated by the opposition right, gave its approval to the article on raising the retirement age.

But French unions wrote in a joint letter to Macron that he and his government had remained "silent" in the face of the mobilisation from the street that has seen six days of mass protests since January 19.

"For our organisations, this lack of response constitutes a serious democratic problem, it inevitably leads to a situation which could become explosive," they said, reiterating a demand for an Elysee meeting with Macron.

On Tuesday, strikes hobbled the country and 1.28 million people took to the streets, according to official figures.

- More all-out strikes planned -
 

A new day of protests has been called for Saturday and unions have urged another day of all-out strikes next Wednesday.

But many of the current strikes are rolling in nature, meaning there was still disruption on French transit systems, trains and airports on Thursday.

Workers at most fuel shipping sites have been on strike although production has not stopped at the refineries, and petrol stations still appear to be stocked.

A vote by both houses of parliament on the law is expected by the middle of the month or by March 26 at the latest.

The government hopes to be able to push through the bill with backing from the right, without having to resort to a controversial mechanism that would bypass a parliamentary vote but risk sparking more anger among voters.

Some two in three people are against the pensions reform, but around the same number believe it will be implemented, according to a poll by the Elabe survey group published on Monday.