France's Notre-Dame cathedral is finally ready to undergo restoration work more than two years after a blaze ravaged the heritage landmark, and remains on course to reopen in 2024, authorities said Saturday, following months of painstaking work to secure the building.

The great mediaeval edifice survived the inferno on April 15, 2019, but the spire collapsed and much of the roof was destroyed.

The focus until now had been on making the cathedral safe before restoration work could begin, which included the strenuous task of removing 40,000 pieces of scaffolding that were damaged in the blaze.

"The cathedral stands solid on its pillars, its walls are solid, everything is holding together," said Jean-Louis Georgelin, head of the public entity tasked with rebuilding the cathedral.

"We are determined to win this battle of 2024, to reopen our cathedral in 2024. It will be France's honour to do so and we will do so because we are all united on this goal."

Notre-Dame de Paris survived the blaze in 2019, but the spire collapsed and much of the roof was destroyed
Notre-Dame de Paris survived the blaze in 2019, but the spire collapsed and much of the roof was destroyed AFP / BERTRAND GUAY

The aim is to celebrate the first full service in the cathedral on April 16, 2024 -- five years after the fire -- despite delays caused by the pandemic and the lead that spread during the blaze.

Authorities will now call for tenders to select the companies to carry out the restoration work.

The cathedral's interior walls and floors will also undergo "a thorough cleaning process" later this month.

Notre-Dame's famous Grand Organ is already being restored, with its 8,000 pipes dismantled and sent to organ builders all over France.

It is expected to be put together again in October 2023, said Georgelin, the former head of France's armed forces who was appointed by President Emmanuel Macron to oversee rebuilding efforts.