Movie-goers and staff have been terrorised in an armed hold-up at a cinema complex in Sydney's north overnight.

Four people armed with a shotgun and a machete stormed the Roseville cinema on the Pacific Highway around 8pm (AEST).

They stormed into the foyer where people were gathering before the start of a Cate Blanchett film.

The bandits demanded cash and personal belongings from staff and patrons before fleeing with cash.

No property belonging to movie-goers was taken and no one was injured.

The robbers fled a 2003 blue Nissan Pulsar, which police say was stolen from a Lane Cove address earlier in the evening.

About two hours later in Sydney's south-west, the same vehicle was used in another robbery at a hotel in Revesby.

In that robbery, three men charged into hotel on River Road and threatened the manager with a shotgun.

The car was later found burnt out on a reserve at Westmead, in the city's west.

Detective Inspector Carole Dowsen says it was a brazen and unusual decision to rob the cinema but largely unsuccessful.

"When they entered one had a hatchet, machete-type hatchet, the other had a sawn off shotgun," she said.

"They threatened them, (saying) 'We'll kill you, we'll shoot you if you don't hand over your money'."

"A couple of the cinema goers refused to hand over their wallets and they just turned and went to another couple of cinema goers and threatened them more severely.

"They did not net a large amount of cash. It's probably why they may have done the second premises after they haven't got the amount of cash that they thought they may have got on the first occasion."

Police say anyone with information on the robberies should contact Crime Stoppers on 1800 333 000.