Traffic in Triq tal-Balal between San Ġwann and Naxxar is being diverted due to a damaged water main.
The Għargħur mayor said on Facebook part of the road had caved in.
But a spokesman for Infrastructure Malta said there was some damage as a result of water seeping out of an old main due to wear and tear. The main was now being replaced.
The road is currently surrounded in controversy as it was being widened without a permit. The project is set to be completed in November.
Read: Trees gone, farmland taken as Tal-Balal gets widened
Għargħur mayor Ġiljan Aquilina said in his post traffic was being diverted into the narrow Għargħur roads creating major inconvenience.
The police confirmed that traffic was being diverted.
Read: ‘Unauthorised’ Tal-Balal road works denounced by heritage watchdog
He said he was in contact with the police to see how the situation could be solved and appealed to the public to use alternative roads in the meantime.