When Christian Frenzel saw news reports showing Notre Dame cathedral burning last month, his first reaction was to get on the phone and call colleagues in France.

Key points: More than $1 billion has been pledged to restore Notre Dame

More than $1 billion has been pledged to restore Notre Dame Experts say restoration is still months away from beginning

Experts say restoration is still months away from beginning An Adelaide stonemason and architectural firm are waiting to hear if they will be involved

The Barossa-based German stonemason was immediately thinking of the aftermath, and the immense amount of work that would be required.

"I rang them out of bed and said: 'What are we going to do with Notre Dame? Are we going to help out?'" he said.

"They didn't even know about it yet. There was quite a bit of surprise."

More than $1 billion has been pledged to restoring Notre Dame cathedral, after it was engulfed by flames on April 15.

The fire caused widespread destruction to the 850-year-old cultural icon, bringing down its 90-metre spire, and Mr Frenzel has no doubts about the scale of the task at hand.

Despite that, he has volunteered his skills free of charge to the French authorities responsible for rebuilding Notre Dame.

"This is one of the rebuilds of the century," he said.

Sparks fill the air as fire brigade members spray water on Notre Dame. ( Reuters: Philippe Wojazer )

Mr Frenzel is part of a very small group of people who possess the technical capability to help repair Notre Dame.

He trained as a cathedral stonemason and has worked on churches around the world, using the traditional tools of mallet and chisel to turn stone blocks into ornate carvings.

He would relish being involved in the Notre Dame restoration because of the prestige and personal satisfaction it would bring.

"A lot of people in the stone industry become sculptors … but cathedral work is very, very different," he said.

"Some people who have worked for 50 years as stone masons would not be allowed to do cathedral work. It is very elite."

He is yet to hear whether his offer has been taken up because it remains unclear how much damage has been done, and how much work will be required.

"A simple gargoyle could take anything from a couple of weeks to a month [to repair]," he said.

"It depends on the intricacies.

"Tracery windows have to be millimetre perfect and if there are flower ornamentations on there, then that will have to be almost perfectly replicated."

Modern design proposal a 'moral dilemma'

Heat from the fire could have caused invisible damage to surviving stone. ( AP: Kamil Zihnioglu )

Mr Frenzel has just finished working on restoring gargoyles at the Smyth Memorial Chapel located inside Adelaide's West Terrace Cemetery.

The work was carried out in conjunction with Adelaide architectural firm Arcuate, which was also interested in tendering for some of the Notre Dame work.

Like Mr Frenzel, Arcuate's director Ian Hamilton is in the dark about whether his company will be called upon.

"There'll be a great deal of work going on to secure the structure and to waterproof the structure. They've got to get a roof over the building," Mr Hamilton told ABC Radio Adelaide.

"In this case we're talking about a building that's seven storeys tall, in real terms.

"There'll be architects and engineers scouring the structure and the walls."

Mr Hamilton said it could take months of "careful research" by French authorities before decisions are made on how to proceed.

"It's painstakingly slow, if they are going to go about it in the correct way and follow heritage principles, which has to be done," he said.

Uncertainty over what form the Notre Dame redesign will take is also contributing to delays, Mr Frenzel said.

The full extent of the damage is still being worked out. ( AP: Christophe Petit Tesson )

The restoration is shaping up as one of France's most controversial projects, because of suggestions that designers might pursue a modern-style rebuild.

"It's a bit of a moral dilemma. To fulfil traditional conservation and restoration guidelines, it has to be rebuilt as it was," Mr Frenzel said.

"Having said that, the spire that burned down was a later addition to Notre Dame, so it already has more modern influences.

"I don't disagree with changes to the roof or the spire structure to make it earthquake and fire proof.

"But if we go too extreme with complete leadlight ceilings, it kind of defeats the purpose. It still is a Gothic cathedral."

'A very huge honour'

Mr Frenzel is based in Williamstown on the edge of South Australia's Barossa region, but his home town is Erfurt in Germany, and he grew up admiring that city's grand cathedral.

After travelling the world in the 1990s to learn from the best pliers of his trade, he settled in South Australia and has carved out a career.

Mr Frenzel works in the tradional way, with mallet and chisel. ( Supplied: Christian Frenzel )

"I travelled and worked on cathedrals most of that time to learn from the old masters," he said.

"I got stuck in Adelaide, the city of churches."

Today, he remains in contact with Europe's cathedral master builders association, which has about 160 members.

If his application to help with repairs is accepted, he would carry out the work in South Australia, and his contributions will be transported to France.

His preference would be to work on the buttresses and the ornamental tracery windows, but he accepts French masons are most likely to get first pick.

"The really fancy work, that will be done there," he said.

Regardless of whether his offer is accepted, he is sceptical of the five-year timeline raised by the French Government.

But the prospect of taking part excites him.

"To carve a piece of stone that's going to go in one of the most famous cathedrals in the world … is a very huge honour," he said.