Motorists and bus commuters in Newtown have been warned to expect major delays during Tuesday's morning peak hour due to emergency repairs on King Street that are expected to take several hours to complete.

A water main burst in a city-bound lane of King Street, near the intersection with Enmore Road, about 5am on Tuesday, forcing the closure of the lane.

Transport Management Centre spokesman David Wright said a power pole would also need to be replaced at the location.

"To allow traffic in both directions to slowly pass this site, only one lane of traffic in each direction will be allowed to pass as repairs take place," Mr Wright said.

"The repair works to both the water main and power pole are expected to take several hours to complete."

He said motorists and bus commuters would experience "significant delays" throughout the morning peak, and further into the day.

The TMC urged motorists to consider using O'Riordan Street and Botany Road as an alternative.

Bus passengers can use their bus tickets on trains on the City Circle, T2 Airport and Inner West, T3 Bankstown and T4 Eastern Suburbs and Illawarra Line.

"Passengers travelling on trains to the Domestic and International Airport stations will need to pay a station fee," Mr Wright said.