Strategic ties and the "Indo-Pacific axis" were high on the agenda when French President Emmanuel Macron met Prime Minister Malcolm Turnbull in Sydney this week.

Key points: If New Caledonia votes to stay, there could be up to two more referenda on independence

If New Caledonia votes to stay, there could be up to two more referenda on independence Only long-term residents of New Caledonia are allowed to vote

Only long-term residents of New Caledonia are allowed to vote A poll last year showed more than half of the population would vote no to independence

That might have something to do with the French President's next stop on his Pacific sojourn: the French territory of New Caledonia, where a vote for independence is fast approaching.

A little more than two hours north-east of Brisbane by plane, New Caledonia has been debating the issue of autonomy for decades, with a fierceness that has occasionally led to violence.

Polls suggest the territory will vote to stay with France at the November 4 referendum, but with a fifth of the population still undecided, it remains unclear which way the vote will go.

But what would a new nation next door mean for Australia?

First off — what is New Caledonia?

Map New Caledonia is just 2,000 kilometres from Sydney.

New Caledonia is a French territory, but it's a lot easier to get to than Paris.

In the south Pacific roughly 2,000 kilometres from Sydney, it's famous for its picturesque tropical beaches and the large reef surrounding its main island of Grande Terre.

Named by Captain James Cook in 1774, it was annexed by France in 1853 and became a penal colony until the turn of that century.

It's estimated 40 per cent of New Caledonia's population of about 270,000 are indigenous Kanak, and 29 per cent are of European origin.

Holding about a quarter of the world's nickel deposits and receiving substantial support from France, New Caledonians enjoy one of the highest GDPs per capita in the Pacific region.

Why do they want to leave France?

Sorry, this video has expired Former Australian consul-general to New Caledonia, Denise Fisher, speaks about the referendum and Emmanuel Macron's visit (Photo: Nic Maclellan)

While New Caledonia might be richer than its neighbours, the indigenous population continues to experience social and economic disadvantages.

Ethnic divisions between the two groups have been an ongoing source of tension for decades.

Rising pro-independence sentiment among the Kanak in the 1980s led to violent unrest, which reached its peak in 1988 with the deaths of 21 people in a hostage crisis in Oueva.

New Caledonian and French leaders eventually signed the Noumea accord in 1998, which set out a timeline for the territory to assume more governmental responsibility, and mandated up to three referenda on independence.

Denise Fisher, a former Australian consul-general in Noumea and now visiting fellow at the Australian National University's Centre for European Studies, said it would potentially be a long process.

"At every turn it's hitting these sensitivities, long-held passions … it is going to be a very tense time in New Caledonia," she said.

What will New Caledonians be asked?

The question New Caledonians will be asked was decided after 15 hours of tough negotiation. ( Flickr: @newcaledoniatourism )

The question New Caledonians will be asked is: Do you want New Caledonia to accede to full sovereignty and become independent? Yes or no.

The yes and no camps came to the agreement in Paris, after 15 hours of tough negotiation overseen by French Prime Minister Edouard Phillipe.

"The pro-independence people really wanted the words 'full sovereignty' to be a part of the question because they don't actually advocate for a strong break with France," said Alexandre Dayant, a research associate at the Lowy Institute.

"They want independence with partnership with France, so the word 'independence' is actually a bit scary for them.

"And the loyalists really wanted the word 'independence' so it would scare people."

Only long-term residents of New Caledonia are allowed to vote in the referendum.

The Kanak population is broadly seen to be pro-independence while New Caledonians with European origins tend to be more in favour of remaining with France.

A poll last year showed more than half of the population would vote no, but that a fifth of those asked were undecided.

Why is Macron's visit significant?

Emmanuel Macron's trip coincides with three anniversaries in New Caledonia. ( Reuters: Thomas Samson )

A visit to New Caledonia by a French President is not unusual, but Mr Macron's visit comes at a particularly important time.

While Mr Macron has expressed his hopes that New Caledonia will remain in France, he's also said that his Government would not take sides in the lead-up to the referendum.

New Caledonia is a Pacific French territory. ( ABC News )

That means despite his visit being just six months before the vote, independence is likely to be the elephant in the room that is rarely addressed — by the President, at least.

"I don't think he has a political agenda going there," Mr Dayant said.

"I think he is going there … to make sure the process is going well."

Mr Macron's trip also coincides with three anniversaries in New Caledonia, including the 30th anniversary of the Ouvea hostage crisis and signing of the Matignon agreements.

What happens when people vote yes or no?

Mr Dayant said no one really knows, which was "a bit disappointing for the [1998 independence] Noumea accord".

"The accord was supposed to prepare all these communities to go to the referendum, now we actually realise that both communities haven't really spoken together," he said.

The flag of New Caledonia. ( ABC News )

If New Caledonia votes to stay, there could be up to two more referenda on independence in the following years.

Anti-independence politician Philippe Blaise said even if French loyalist groups took the day, they would need to accept the win with humility.

"Even if the idea of independence loses in November, we will be responsible for the welfare of everyone in New Caledonia, including the Kanaks," he said.

"On the 5th of November, we will have to sit around a table and start to talk how to ensure the best future for the people, all the people, how to resolve the problems of inequalities, of education, and so we will be up to the job I think. "

Why should Australia care?

New Caledonians enjoy one of the highest GDPs per capita in the Pacific region. ( Flickr: Rick Sharloch )

A close ally, France's presence in the Pacific with its overseas territories represents a reassuring stability to Australia.

"There's no doubt [the Noumea accord has] presided over 30 years of peace and stability on our doorstep and for Australia this has great strategic value," Ms Fisher said.

Some are concerned a vote for independence could see New Caledonia join the list of Pacific countries grappling with debts owed to China through concessionary loans for infrastructure projects.

News last month of a Beijing-funded wharf in Vanuatu that was large enough to accommodate an aircraft carrier sparked fears China was contemplating a permanent military presence in the country.

"New Caledonia, with its maritime zone, is a big element of French diplomacy," Mr Blaise said.

"We are very concerned about the threat of Chinese influence in the Pacific Ocean and we think that France has a part to play in the new alliance between India, Japan and Australia against the emergence of this new threat."