A cleaner who escaped from four gunmen who were attempting to rob a warehouse on Sydney's lower north shore was hit by a car as he tried to run away, police say.

The male cleaner was leaving work at an electronics warehouse in Herbert Street, St Leonards, about 10.20pm yesterday when he was approached by four men wearing balaclavas and carrying guns, police said.

The men forced the cleaner back inside the warehouse.

While the men were trying to steal some electrical items, the cleaner escaped and ran to the street.

Police said the cleaner was hit by a dark car, possibly driven by someone connected to the robbery.

He alerted a passing motorist and was taken to Royal North Shore Hospital with cuts and bruising.

He is expected to be released today.

The four men left the area empty-handed.

A high-performance Audi sedan was found burnt out on Woodley Street, St Peters, about 1am. Police are investigating whether it is the same car used in the attempted robbery.

Anyone with information is asked to phone Crime Stoppers on 1800 333 000.