Rescue crews resumed digging through the rubble of a collapsed factory in Pakistan Friday as officials said they expected to find at least two dozen more bodies, with the death toll standing at 23.

Rescue crews resumed digging through the rubble of a collapsed factory in Pakistan Friday as officials said they expected to find at least two dozen more bodies, with the death toll standing at 23.

More than 100 survivors have already been pulled from the debris of the four-storey Rajput Polyester polythene bag factory near the Punjab provincial capital of Lahore after it came crashing down on Wednesday evening, trapping dozens of people inside.

But hopes were fading for anyone left alive as rescuers scrabbled through the debris.

Soldiers and rescuers were preparing to clear the rubble in front of the factory and move towards the rear of the building where they fear they will discover more victims.

It was unclear how many people were in the building when it collapsed or how many - dead or alive - may still be trapped, but officials have said at least 150 people were in the factory when it came down.

Punjab chief minister Shahbaz Sharif said the factory may have suffered structural damage in the October 26 quake which killed almost 400 people across Pakistan and Afghanistan.

At least 24 people died last year when a mosque collapsed in the same city, while more than 200 people lost their lives, mostly due to collapsed roofs, following torrential rain and flooding in 2014.