The intermittent leak in the northbound Sta Venera tunnel has reappeared, mere weeks after water ceased dripping.

The leak is located about 100 metres into the same tunnel and made its return on Tuesday with a constant shower pouring over the central strip.

When the leak made an impressive debut following heavy rain on September 29 last year, the outflow was so strong the northbound tunnel had to be closed for traffic.

The water appears after heavy rain falls, however it does not stop once the rain subsides and can go on for weeks at a stretch.

The problem falls on the lap of two authorities, Transport Malta and the Water Services Corporation. None of them was able to come up with a conclusive explanation but the WSC is now clearly passing the buck over to the transport authority.

Investigations carried out on samples taken by the WSC established that the water leaking into the tunnel was "considerably different" from its mains or drainage pipes running in the area.

The corporation also ruled out a borehole near the Fleur-de-Lys roundabout and another in Antonio Miruzzi Street and concluded that it "could be contaminated rain water that is somehow finding its way through fissures above the tunnel".

When contacted yesterday, a spokesman said the case was closed for the corporation, pointing out that it was obvious the problem is linked to rain and therefore not its problem.

Transport Malta did not have an explanation for what is causing the leak either when the problem first developed but said the dripping was more of a "minor inconvenience" rather than a risk to motorists.

Still, the transport authority had said it would consider installing a water catchment system to prevent the leak from spilling over to the road but nothing has been installed so far. Fresh questions sent to the authority about the latest leak have not been answered.