As further rainfall continued to fall on Monday afternoon, fire service personnel and roads service staff worked to pump the excess water out of the thoroughfare and remove sludge and debris.

A car - with a taxi notice - was clearly visible as the water began to subside.

At the height of the torrential rainfall on Saturday, the new underpass which had only recently became operational, was submerged in up to 20ft of water.

Extra police resources were allocated to ensure traffic remained free flowing as arrangements on the busy route reverted to a system similar to that which was in place before the underpass opened.

Prior to rush hour, traffic was relatively free flowing as vehicles converged on the Broadway roundabout.

Many commuters Belfast-bound had apparently opted to travel to the city via alternative routes in expectation of delays.

An investigation has been ordered by Roads Minister Conor Murphy into how the underpass flooded so dramatically.

The flooding has been blamed on the overflowing of a nearby river diverted for the Westlink upgrade.

As many as five vehicles were trapped in the underpass as water engulfed the new 120m tunnel.