Germany reveals it will keep border controls ‘indefinitely’ as Merkel faces backlash over open door policy

200 migrants in lawsuit against Federal Office for Migration and Refugees

They have been waiting more than year on decision whether they can stay

Some cases held in Cologne which suffered mass sex attacks by migrants

Comes as German president said it was 'necessary' to limit refugee influx

The German government has announced that border checks on migrants will 'continue indefinitely' as the country faces unprecedented levels of immigration.

Speaking to German radio station MDR, interior minister Thomas de Maiziere admitted the new restrictions, introduced in September, will remain for the foreseeable future.

He said 'I don't foresee a moment when we can end it.'

The admission comes as Chancellor Angela Merkel is coming under increasing pressure domestically from opponents to the country's liberal immigration regime, and from migrants complaining the process is taking too long.

According to EU Observer, many German politicians want to see dramatic reductions in the number of people seeking asylum from the war-torn Middle East.

Meanwhile, indignant refugees in Germany are suing Angela Merkel's government, claiming it is taking too long to process their asylum applications.

More than 200 migrants in the state of North Rhine-Westphalia have launched a lawsuit against the Federal Office for Migration and Refugees because they have been waiting over a year for a decision on whether they can stay in Germany.

The cases being heard in several courts across the state – including Cologne which witnessed a terrifying frenzy of sexual attacks against women by migrants on New Year's Eve – allege 'inactivity' on the part of officials.

News of the lawsuits came on the same day that German president Joachim Gauck told global financial and political players gathered at Davos for their annual conference that it is 'morally and politically necessary' to limit Europe's refugee influx.

Failure to do so, he warned, gave ammunition to extremists, adding: 'Limits are not unethical: they help to maintain acceptance within society.'

This goes against the policy of Chancellor Merkel who refuses to say just how many people are enough, even as her popularity slips and her countrymen fear that they can cope with no more.

Germany's refugee authortiy (BAMF) is struggling to cope with the backlog of refugee applications following the arrival of more than million people last year. In all there are 360,000 unprocessed applications in the bureaucratic logjam.

Even the justice minister for North Rhine-Westphalia, Thomas Kutschaty, said he understood the anger of migrants, adding; 'Uncertainty about when an asylum application will finally be decided drives many people to despair.

'It can't be the case that asylum seekers are forced to take legal action against the state after crossing the border, so that it finally makes a decision about their application.'

Court sources told Germany's Rheinische Post newspaper that BAMF is often spurred to process claims more quickly if it is threatened with legal action.

Read more: Angela Merkel being sued by migrants over time taken to process asylum claims