Motorists have been warned to expect major delays on Victoria Road in Ryde during Monday morning's commute after a water main burst, closing a number of lanes.

All city-bound lanes and two west-bound lanes were initially closed when the water main burst near the intersection of Victoria Road and Blaxland Road about 4am.

Just before 6.30am, two lanes in each direction were re-opened, with one lane in each direction remaining closed.

The Transport Management Centre (TMC) said motorists should expect delays through the morning peak and follow the direction of traffic controllers on site.

Motorists also can not turn left from Blaxland Road onto Victoria Road.

TMC spokesman Marco Spadaccini said city-bound traffic had banked up about one kilometre during the morning, but just before 8am the queue had eased to about 500 metres.

The fact that it was school holidays and there was less peak-hour traffic on the road had helped the situation, he said.

"If school was in, it would be getting critical in the next 15 minutes," he said.

There are significant delays to bus services. Bus tickets can be used on the North Shore and the Northern lines, Sydney Trains said.

Emergency services and Sydney Water crews are on site trying to fix the burst water main, before the road surface can be fixed. The lanes will remain closed at least for the morning peak, Mr Spadaccini said.

Sydney Trains is recognising Sydney Buses tickets along #NorthShoreLine & #NorthernLine due to a burst water main on Victoria Road. — T1 Sydney Trains (@T1SydneyTrains) September 28, 2014