British authorities have arrested hundreds of people in a “week-long crackdown” on asylum-seekers taking jobs for delivery firms.

Immigration enforcement officers stopped and questioned 1,780 individuals between July 20 and 27 and 280 people were arrested, the interior ministry said, adding asylum support was being reviewed for 53 of those detained.

The operation was part of a push by the government to tackle illegal migration which also includes new legal requirements for companies to verify workers' immigration status.

Prime Minister Keir Starmer is facing pressure to show voters he can counter illegal immigration with support rising for Brexit campaigner Nigel Farage's Reform UK party.

"This government is making sure rules are respected and enforced," border security minister Angela Eagle said.