France announced Monday it would open two shelters for migrants sleeping rough around the port of Calais, relenting to pressure to improve the lot of hundreds of people hiding from police.

The centres will be located in the towns of Troisvaux and Bailleul, situated about 50 miles inland from Calais, Interior Minister Gerard Collomb said.

Each will have a capacity of 300, he told reporters, estimating the number of migrants currently in the northern port at between 350 and 400.

France's highest administrative court ruled the government and Calais must provide hundreds of migrants with drinking water, showers and toilets (file photo of 'The Jungle')

His announcement came hours after France's highest administrative court ordered the state to provide drinking water, showers and toilets for the migrants, saying that its refusal so far to do so 'exposed them to inhuman and degrading treatment.'

The Council of State was ruling on an appeal by the interior ministry and the city of Calais against an injunction issued by a court in Lille last month.

In its decision Monday the Council of State upheld the order sought by a group of charities, saying that migrants were developing skin diseases such as scabies and festering wounds as they had no way of washing themselves or their clothes.

The situation was causing 'serious psychological problems', it added, calling the state's failure to address the situation 'a serious and clearly illegal blow to a basic right'.

Calais' Mayor Natacha Bouchart said she would ignore the order.

'The decision by the Council of State is unfair to the people of Calais because it threatens them with the emergence of yet another Jungle,' she said, referring to the sprawling migrant camp from which over 6,000 people were evacuated last year.

'In the absence of a national and European policy offering a global solution on controlling immigration, Calais will not implement the injunctions,' she declared in a statement.

Collomb too had argued that the provision of services could have a pull effect on migrants who trek across Europe to Calais in the hope of stowing away on a truck crossing the Channel to England.

Charities have been fiercely critical of the squalid conditions facing hundreds of migrants who have returned to the port city (file photo of 'The Jungle')

On Monday, the minister said that the addition of two new shelters to the around 450 already in operation around the country would help speed up the processing of asylum claims from those migrants who wished to stay in France.

'We do not want to repeat the bad experiences of the past,' he warned, alluding to the squalid Jungle.

He also announced an internal police investigation into claims of excessive force being used by officers against the migrants in Calais.

Charities have been fiercely critical of the squalid conditions facing hundreds of migrants who have returned to the port city after government bulldozers razed the camp known as the 'Jungle'.

A local court said this year that the authorities must provide access to water, prompting an appeal by the interior ministry and Calais commune.

Rejecting that appeal, the Conseil d'Etat ruled that the treatment of migrants was inhuman.

Migrants seen around the truck stops in Marck, Calais, earlier this year

'The Conseil d'Etat considers that these living conditions reveal a failure by the public authorities that has exposed these people to inhuman or degrading treatment,' the court said in a statement.

'These shortcomings are a serious and unlawful infringement on a fundamental freedom.'

It said the lower court was within its rights to order the provision of toilets, drinking water and showers.

France has avoided the brunt of Europe's migrant crisis, receiving a fraction of the asylum seekers handled by countries like Italy and Germany.

While Macron has called for migrants to be treated with dignity, his own government has taken a tough stance, refusing to open a new migrant reception centre in Calais, saying it would act as a magnet for other migrants.

Last week, Human Rights Watch pressed France to end what it described as recurrent police violence against migrants in Calais, where hundreds have returned despite the demolition of a sprawling camp.

Many of the Calais migrants seek a better life in Britain.

The European Union is struggling to find a coherent answer to a migration crisis that has tested cooperation between member states. Macron has instructed his government to speed up France's asylum process.