Sydney has passed the first major test of sweeping changes to bus timetables and routes, with no major incidents during the morning peak.

While the changes occurred on Sunday, the biggest test for the network was on Tuesday, when more than 630,000 commuters returned to the city after the long weekend.

Transport Minister Andrew Constance said it was still early but there had not been any major disruptions.

"It's been a pleasing first peak and I thank commuters for responding in the way they have. It's one peak down but many more to go," he said.

"I'm urging commuters to avoid the shoulders of the peak and plan their trip home tonight."

Mr Constance visited the Transport Management Centre in Eveleigh early this morning to get an update from staff on how passengers and drivers had coped with the new timetables and routes.

The morning commuter peak in Sydney's CBD is between 8am and 9am.

State Transit chief executive Peter Rowley said the plan had gone "very, very well" and he expected it to continue to do so.

"No issues this morning – everyone's been very patient," he said. "Everyone is heeding the warnings that have been put out there, and it's going very well."

Mr Rowley said the transport modelling conducted for the new bus plan showed new routes should be able to handle the extra buses during the peak hour.

The Rail, Tram and Bus Union's divisional secretary, Chris Preston, agreed the bus network had performed better than expected.

"At this early stage, the buses seem to be getting around the city," he said.

While the network was performing well, Mr Preston said there had been "conga lines" of passengers walking along York Street from Wynyard, where bus routes now ended, because they did not want to have to pay an extra fare to catch another bus to their final destination.

M30 buses, the only ones that still travel through the CBD, were "chock-a-block with full standing loads".

Mr Preston had warned on Monday that the "whole CBD will be a mess".

The government had also warned commuters to expect significant disruptions on Tuesday. It believes it will be at least a month before the changes are fully bedded down, because such a large number of Sydneysiders have had to adjust their behaviour.

The bus network has been changed to allow construction work to begin on a $2.1 billion light rail project, which will connect Circular Quay to Randwick and Kingsford via George Street and Central.

It means almost all bus commuters travelling into the CBD in the morning have been affected by the closure of parts of George Street to traffic for the construction of the light rail line.

Sydney Business Chamber executive director Patricia Forsythe said the system was working well and passengers had decided to catch buses to the CBD from the northern beaches early on Tuesday morning.

"It does look like it's flowing well, and that's the message from people getting off the buses," she said.

"The Harbour Bridge is flowing well and that is always the test because that's where you get the build-up."

Kevin Sinnott, who was travelling from Dee Why, said the bus journey "didn't really feel much different" to his usual commute to the city.

"It felt pretty much the same," he said.

Sydney Trains chief executive Howard Collins said an important aspect had been to get the trains to match the bus services.

The 12-kilometre light rail line is due to be opened by early 2019, and is intended to help ease congestion in Sydney's CBD by removing 220 buses during the morning peak travel period.

How was your commute? Comment below: