The fund set up to rebuild the fire-ravaged Notre Dame Cathedral in Paris is set to reach €1bn (£870m) today as donations continue to pour in from billionaires, corporations and ordinary citizens.

The French president Emmanuel Macron has set out an ambitious five-year deadline to get the difficult and costly restoration work done.

On Wednesday Stéphane Bern, the TV personality who helped launch the fund to help pay for the reconstruction, told French media: “We are about 900 million euros and the billion mark will be exceeded today.”

French companies Total and L’Oreal have promised to each donate €100m (£87m) euros, while the billionaire families who own LVMH Group, Kering and L’Oreal pledged a combined total of €500m (£435m).

The French government is gathering donations and setting up a special office to deal with offers of assistance.

Notre Dame fire: What was lost and what was saved Show all 13 1 /13 Notre Dame fire: What was lost and what was saved Notre Dame fire: What was lost and what was saved Statue of Saint Denis Notre Dame https://commons.wikimedia.org/wiki/File:Paris_-_Cath%C3%A9drale_Notre-Dame_-_Portail_de_la_Vierge_-_PA00086250_-_003.jpg Thesupermat/CC-BY-SA Thesupermat/CC-BY-SA Thesupermat/CC-BY-SA Notre Dame fire: What was lost and what was saved "Close up of Virgin Mary and Baby Jesus statues at Notre Dame Cathedral in Paris, France. Other images of the Notre Dame Cathedral:" gregobagel Getty Images/iStockphoto Notre Dame fire: What was lost and what was saved Safe: Rose windows Among the most famous architectural features of the Gothic masterpiece, the stained glass rose windows are treasured artworks. The three rose windows, which date back to the 13th century, adorn the north, south and west facades. There were hopes the windows had escaped being destroyed by the fire after firefighters stopped its spread. Photos the following morning suggested the circular window of the nave had remained intact. AFP/Getty Notre Dame fire: What was lost and what was saved Destroyed: Irreplaceable wooden roof Crowds of tourists and Parisians watched in horror as the spire and roof of Notre Dame cathedral came crashing down to the ground. EPA Notre Dame fire: What was lost and what was saved Safe: Descent from the Cross The cross and statue on Notre Dame's high altar - sculpted by Nicolas Coustou in 1723 - were believed to have survived in tact despite being surrounded by smoke and debris. Reuters Notre Dame fire: What was lost and what was saved Safe: Great Organ With nearly 8,000 pipes, some dating back to the 1700s, Notre Dame's master organ is one of the largest in the world. The monumental instrument, the largest in France, was fully restored in 2013 with each pipe cleaned. Paris' deputy mayor, Emmanuel Gregoire, said the instrument remained intact following the fire. AFP/Getty Notre Dame fire: What was lost and what was saved Safe: Bells Housed in the two western towers, Notre Dame's bells have rung out at key moments in France's history. Emmanuel, the largest bell, was lifted into the south tower in 1685 and weighs over 23 tonnes. The fire was prevented from spreading to the bell towers. AFP/Getty Notre Dame fire: What was lost and what was saved Safe: Crown of Thorns Believed to be a relic of the wreath of thorns placed on the head of Jesus Christ at his crucifixion, the object was stored in the cathedral's treasury. French King Louis IX brought the relic, which is contained in an elaborate gold case, to Paris in 1238. The Crown of Thorns was saved and has been taken into safekeeping. AP Notre Dame fire: What was lost and what was saved Safe: Tunic of Saint Louis The tunic allegedly worn by Saint Louis IX as he brought the Crown of Thorns to Paris was kept inside the cathedral. It has been saved. AFP/Getty Notre Dame fire: What was lost and what was saved Safe: Statues on the roof The week before the fire, religious statues set atop the cathedral were removed for the first time in over 100 years as part of the restoration project. A 100-metre-high crane lowered the copper statues representing the 12 apostles and four evangelists onto a lorry. AFP Notre Dame fire: What was lost and what was saved Destroyed: Spire Crowds of tourists and Parisians watched in horror as the spire and roof of Notre Dame cathedral came crashing down to the ground. EPA/I Notre Dame fire: What was lost and what was saved Unknown: Choir screen It is not known what happened to the detailed choir screen at Notre Dame cathedral. AFP/Getty Notre Dame fire: What was lost and what was saved Some of the artworks from Notre-Dame sheltered as the fire devastated the cathedral AFP/Getty

It comes as Pope Francis thanked rescuers who put their lives at risk to salvage the cathedral from a devastating blaze, and said he was eager to see it restored.

“May the Virgin Mary bless and support the work of reconstruction. May it be a harmonious work of praise and glory to God,” he told tens of thousands of people in St. Peter’s Square on Wednesday.

Mr Macron is holding a special Cabinet meeting on Wednesday dedicated to the disaster, which investigators believe was an accident possibly linked to renovation work.

Emmanuel Macron speaks to the nation about restoring Notre Dame (AP)

In a televised address to the nation on Tuesday night, the president said “we will rebuild Notre Dame cathedral even more beautiful”.

The French government will open the redesign of the Notre Dame’s iconic roofline to international architects after Monday night’s blaze, the prime minister announced on Wednesday.

“The international competition will allow us to ask the question of whether we should even recreate the spire as it was conceived by Viollet-le-Duc,” said Edouard Philippe. “Or if, as is often the case in the evolution of heritage, we should endow Notre-Dame with a new spire.”

Some criticism has already surfaced among those who say the money could be better spent elsewhere, on smaller struggling churches or workers.

Meanwhile the president’s five-year deadline – which happens to coincide with the 2024 Paris Olympics, which the government wants to make a major showcase – struck some as unrealistic.

Pierluigi Pericolo, in charge of restoration and security at the St. Donatian basilica in Nantes, said it could take two to five years just to secure Notre Dame, given its size.

“It’s a fundamental step, and very complex, because it’s difficult to send workers into a monument whose vaulted ceilings are swollen with water,” he told France-Info.

A fire fighter makes his way on a balcony of Notre Dame cathedral Wednesday (AP)

“The end of the fire doesn’t mean the edifice is totally saved. The stone can deteriorate when it is exposed to high temperatures and change its mineral composition and fracture inside.”

Some 30 people have already been questioned in the investigation, which the Paris prosecutor warned would be “long and complex”.

Construction teams brought in a huge crane and a delivery of planks of wood to the site Wednesday morning.

Firefighters are still examining damage and shoring up the structure after Monday's fire collapsed the cathedral’s spire and destroyed the roof.

Remarkable footage shows firefighters battling Notre Dame flames

Among those questioned are workers at the five construction companies involved in work renovating the church spire and roof that had been under way when the fire broke out.

A plan to safeguard the masterpieces and relics was quickly put into action after the fire broke out.

The Crown of Thorns, regarded as Notre Dame’s most sacred relic, was among the treasures quickly transported after the fire broke out, authorities said. Brought to Paris by King Louis IX in the 13th century, it is purported to have been pressed onto Christ's head during the crucifixion.

The cathedral’s famous 18th century organ that boasts more than 8,000 pipes also survived. Some of the paintings and other art works are being dehumidified, protected and eventually restored at the Louvre.