Home Secretary Sajid Javid has confirmed he is asking officials to draw up an urgent case for introducing the new ban around Idlib province in northwestern Syria and others areas in the northeast of the country.
The move comes amid an upsurge in violence around Idlib in particular, where Russian-backed Syrian government forces have launched an offensive against rebel fighters.
On Friday, the United Nations warned of a “humanitarian crisis” and urged the Syrian and Russian governments to give assurances that the bombing of hospitals and schools would stop.
The Counter-Terrorism and Border Security Act 2019, which became law earlier this year, created a new power allowing the home secretary to ban British nationals from travelling to – or remaining in – specific designated areas.
Mr Javid said: “I’ve asked my officials to work closely with the police and intelligence agencies to urgently review the case for exercising this power in relation to Syria, with a particular focus on Idlib and the northeast.
“So anyone who is in these areas without a legitimate reason should be on notice.”
In order to use the power, the home secretary would need to be satisfied that it is necessary to restrict UK nationals and residents from a specific area and his recommendation would need to be ratified by parliament.
An individual found to have entered or remained in a designated area could face up to 10 years in prison if convicted.
The new law was introduced to counter the problem of hundreds of foreign fighters heading off to overseas trouble spots, with little fear of prosecution.
Officials estimate more than 900 British citizens travelled out to take part in the conflict in Syria.
Around 400 have since returned, but difficulties in securing any evidence of wrongdoing in an area of lawlessness has meant less than 10% of those who have returned have been prosecuted.
Under the new law, prosecutors will only have to prove a person has been in a designated area without good reason.
There will be exemptions to the travel ban, allowing the likes of legitimate aid workers, journalists, or those attending a family funeral, to enter such areas.
Mr Javid will give more details of how he expects the new law to operate during a speech in central London on Monday morning, where he will also reassure his audience of extremism experts and security officials that, whatever Britain’s future relating to the EU is, the UK will continue to be a powerful international partner in dealing with security threats.
He is expected to say: “From terrorism, to crime, to hostile state activity, we are facing international problems, and they require an international response.
“As these threats become more global we all rely on an international system of defence, policing, security and intelligence. A safety net based upon cooperation, and unity.
“More than any other country on Earth, the UK has a coherent, connected approach to intelligence and security and when threats appear, the world still turns to the UK for leadership, support, and action.”
Despite the large scale dismantling of Islamic State in Syria and Iraq, security officials warn the UK terror threat will continue to be very significant for the foreseeable future.
The recent bombings in Sri Lanka, which have been linked to IS, and the reappearance of the group’s leader Abu Bakr al Baghdadi, have shown that the fragmentation of the terror network has not weakened its determination to launch attacks around the globe.