It follows a report of criminal damage at a derelict property in the University Street area of south Belfast this morning.
Inspector Shaw of PSNI South Belfast said: “Shortly after 8.25am, it was reported that a derelict premises was on fire in the area.
“No one is believed to have been injured during the incident, but there is a risk of the building collapsing.
“Motorists are advised to avoid the area and to seek alternative main routes for their journey with the road closed at the Unuversity Street/ Sandhurst Road junction.
“The male is currently assisting police with their enquiries.”