Migrant minors leave the temporary housing before their transfer by French authorities to reception centres across the country at the end of the dismantlement of the camp called the "Jungle" in Calais, France, November 2, 2016. REUTERS/Pascal Rossignol

By Matthias Blamont

PARIS (Reuters) - Some 300 to 400 migrants, mostly unaccompanied children, have made their way back to Calais in northern France over the past few weeks in the hope of reaching Britain, non-government associations say.

France moved more than 6,000 migrants, many fleeing poverty and war in their homelands, from the site of a makeshift camp in the port city last October to reception centers around the country to calm growing local anger.

The migrants from the Middle East, Asia and Africa have streamed into Calais for years, hoping to cross the short stretch of sea to Britain by leaping onto trucks and trains, or even walking through the tunnel under the Channel.

Police forces are still deployed permanently in the area.

"We believe some migrants are coming back and that 300 to 400 of them are currently in the region. Most of them are teenagers or young adults," Lucie Favry, from local aid association Utopia 56, told Reuters.

A precise figure was difficult to come by because many were in hiding from police patrols while others had already made it across to Britain, she said.

Yolaine Bernard, who works with the NGO Salam, said she and her colleagues were handing out more than a hundred meals daily to migrants turning up.

"We haven't been counting them all, but we see new faces all the time, so we are definitely talking of hundreds of people and I think there are more and more migrants around," she said.

"Authorities are not doing anything since the jungle was torn down. We are on our own here," she added. The 'jungle' is the colloquial name for the make-shift camp that was dismantled.

The regional government in Calais refused to confirm numbers and said local authorities were wary of sending any kind of message suggesting migrants would benefit from special treatment if they came back.

"We are now in a normal context that is the French rule of law," she said.

Several associations and public figures openly criticized the action of the French government when the "jungle" was closed last year, while a row erupted between Paris and London over the fate of several minors with ties in Britain.

(Editing by Richard Balmforth and Hugh Lawson)