The 10-day trial will allow Opal card holders to get on buses from their back or middle doors, rather than only the front, during the afternoon peak at seven city stops from Monday.

These doors are usually plastered with "no entry" stickers but the state government hopes opening them will improve traffic flow in the city and reduce the time buses wait at stops.

A marshal, or supervisor, will be placed at each stop to monitor boarding through the rear doors. Bus users who use paper tickets will still only be able to enter through the front of the bus.

Commuters waiting for westbound buses at Druitt Street, before Kent Street, on Thursday evening seemed overwhelmingly pleased with the chance to pick their doors. They were all offered leaflets explaining the trial.

Five Dock resident Christian Vizcarra, who only recently switched his car for the bus, said he was "all for it" and thought it would help dilute long bus queues.

"Most people are honest and they tap on and tap off and I don't see a problem with it," he said.

"I think it's a great idea. It's a needed idea. I just heard someone saying before in the line that they were from Melbourne and they allow that in Melbourne on the tram. Obviously it works well down there, so hopefully it will work well down here," another regular bus user, Cindy Booles, from Hunters Hill said.

Another Hunters Hill resident, Jennifer Williams, who only catches the bus every six weeks, said the trial could reduce the scrum that sometimes forms to enter the bus.

"You would end up with two aisles going onto the bus instead of everyone being anxious to get on the front door," she said.

"I think as long as there is a doorway for people to exit the bus there shouldn't be a problem with."

Bus drivers, however, are less thrilled with the plan. They are concerned that the trial could be dangerous and disruptive.

Chris Preston, the bus and tram division secretary of the Rail Tram and Bus Union, said drivers were fearful buses would be overloaded as it would be harder to monitor passenger numbers with all doors open. Long delays and heated confrontations could be caused if drivers then had to ask some commuters to leave the bus.

There was also the risk that the trial might mislead some bus users to thinking that all-door boarding now applied across all stops on the network, Mr Preston said.

"There's also the risk that the driver can't see if you're running to get on the back door, so [he or she] shuts it and you end up planting your face into the rear door, or even worse you get your arm or leg caught," Mr Preston said.

"We're prepared to try it but we're sceptical it's going to work."

The trial will run on week days from 4pm to 7pm from June 15 to 26.

The bus stops to be used in the trial are: 

• Westbound on Druitt Street, before Kent Street
• Wynyard Stand R (northbound on Clarence Street, before Margaret Street)
• Wynyard Stand Q (northbound on Clarence Street, after Margaret Street)
• Queen Victoria Building Stand B on York Street
• Queen Victoria Building Stand C on York Street
• Queen Victoria Building Stand E northbound on George Street, before Market Street
•  Elizabeth Street southbound before Kippax Street (outside Aurora Hotel)