French unions on Thursday staged a new day of disruption against President Emmanuel Macron's pension reform after he defiantly vowed to implement the change, with refineries at a standstill and mass transport cancellations.

Interrupted supply from refineries has raised concern over fuel shortages for planes at Paris airports, adding to a growing list of headaches in the crisis that include growing piles of rubbish in Paris and questions over the looming state visit of King Charles III.

Macron on Wednesday said he was prepared to accept unpopularity because the bill raising the minimum retirement age from 62 to 64 was "necessary" and "in the general interest of the country."

On Thursday, protests were planned across the country, in the latest day of nationwide stoppages that began in mid-January against the pension changes.

Some 12,000 police, including 5,000 in Paris, were to be deployed during the day, Interior Minister Gerald Darmanin has highlighted.

In early Thursday, protesters blocked road access to Terminal 1 at the capital's Charles de Gaulle airport, French television pictures showed.

Paris airport Charles de Gaulle occupied, roads blocked,
also Beltways around Toulouse and Chambery blocked

It’s Thursday morning and there’s more to come https://t.co/ze9FKqzS9e pic.twitter.com/jhlw48u9iZ

— Timothy Robert (@timingnl) March 23, 2023

Half of all high-speed trains were canceled, national railway operator SNCF indicated, after union sources reported around a third of staff would be striking. At least half the trains into Paris from the suburbs were not running.

Paris municipal garbage collectors have pledged to uphold a rolling strike until Monday, as thousands of tonnes of rubbish remain in the streets.

Acting on Macron's instructions, French Prime Minister Elisabeth Borne invoked an article in the constitution a week ago to adopt the reform without a parliamentary vote.

The government on Monday narrowly survived a no-confidence motion, but the outrage has initiated the biggest domestic crisis of Macron's second term.

Read more: France's Constitutional Council mulling passing pension reform

Airport fuel 'under pressure'

A survey on Sunday showed Macron's personal approval rating at just 28%, its lowest level since the height of the anti-government "Yellow Vest" protest movement in 2018-2019.

Blockades at oil refineries were also to continue, with only one such TotalEnergies site in four working in the country.

The Ministry of Energy Transition on Thursday warned that kerosene supply to the capital and its airports was becoming "critical".

The Directorate General of Civil Aviation has warned that its fuel stocks at the two main Paris airports are "under pressure" and urged planes to fill up at foreign stopovers.

Spontaneous protests have broken out on a daily basis in recent days, leading to hundreds of arrests and accusations of heavy-handed tactics by police.

Amnesty International has expressed alarm "about the widespread use of excessive force and arbitrary arrests reported in several media outlets."

Paris police chief Laurent Nunez on Thursday denied this, claiming that the security forces only detained people from "gatherings towards committing violence."

On Wednesday evening, hundreds again took to the streets in Paris, the southeastern city of Lyon, and the northern city of Lille, the authorities said.

Read more: Iran slams France's hypocrisy, brutality during anti-reform protests

'Disdain' for thousands of people

While France's Constitutional Court still needs to give the final word on the reform, Macron told the TF1 and France 2 channels in a televised interview on Wednesday that the changes needed to "come into force by the end of the year."

Backtracking on earlier comments that the crowds demonstrating had "no legitimacy", the French President said that organized protests were "legitimate", but violence should be condemned and blockages should not impede normal activity.

"We cannot accept rebels or factions," he added.

In response, Philippe Martinez, head of the hard-line CGT union, considered that Macron's remarks showed "disdain for the thousands of people who have been protesting."

The tensions have also raised questions over whether France can host the UK's King Charles III when he arrives Sunday for his first foreign state visit as monarch.

The government has claimed that the reform is necessary to keep the system from slipping into deficit and to bring France in line with its European neighbors, where the legal retirement age is typically higher.

Critics however argue that the changes are unfair to people who start working at a young age in physically challenging jobs, and to women who interrupt their careers to raise children.

Read more: Nearly a thousand protesters detained in France since Thursday