French President Emmanuel Macron is re-introducing compulsory national military service for young people in France, the government said today.

By bringing back national service two decades after it was scrapped, Macron is fulfilling one of his campaign pledges.

During his presidential campaign, Macron promised to make all young people spend a month getting 'a direct experience of military life with its know-how and demands'.

Keeping promises: The re-imagined national service, one of President Macron's campaign pledges, will last a month and be an experience of 'military life' for young French people

He billed it as a way to build social cohesion and patriotism in a country battling deep divisions, by bringing young people from different backgrounds together in a barracks.

But the proposal raised hackles in the army, which is already stretched thin by anti-terrorism operations in the Middle East and West Africa as well as patrols against jihadists at home.

Opposition parties and experts also warned of the costs involved in training up 600,000 and 800,000 youngsters a year.

Last week, Defence Minister Florence Parly appeared to cast doubt on the scope of the plan, saying it would 'probably not be obligatory'.

But government spokesman Benjamin Griveaux on Tuesday insisted that Macron would not beat a retreat on the proposal.

Military fan: Macron watch the annual Bastille Day military parade along Avenue des Champs-Elysees in Paris last July in the company of U.S. President Donald Trump

'It will be universal... and it will be obligatory,' he told Radio Classique, adding that a taskforce would come up with suggestions on how to implement it by the end of April.

But in a sign not all young people may be forced to don uniform he said that the service 'could also be a civic engagement', being about 'how you give your time usefully to the nation'.

France's last conscripts were demobilised in 2001, ending nearly a century of military service which saw millions of men put through their paces.

While some French men look back fondly on their stint in the army, many middle-class youths called in well-placed contacts - or feigned mental health problems - to duck out of it.

In January, Macron - the first French president not to have been called up to serve, having come of age after it ended - insisted he was not trying to resurrect the tradition which was ended by ex-president Jacques Chirac.

He said his aim was to give young men and women alike 'causes to defend and battles to fight in the social, environmental and cultural domains.'

The government plans to trial the programme in 2019.