North West Metro months from opening

The North West Metro is just months from opening to the public after a test with a driverless train was completed.

A train travelled the entire route from Rouse Hill through the Hills District to Chatswood today, nine years after the Liberal government pledged to build the new line.

"In peak hour, anywhere from between 30,000 to 40,000 people will no longer have to rely on their cars," NSW Premier Gladys Berejiklian said, adding the project was $500 million under budget.

Buses have been replacing trains between Epping and Chatswood since September but Minister for Transport Andrew Constance said commuters will be back on the train between April and May this year.

He said the line still needs to undergo extensive testing.

"It is a driverless train - it's got to meet the requirements of the national safety regulator," Mr Constance said.

The next stage of the metro line will go under Sydney Harbour, through the city and out to Bankstown.

However, if Labor are elected - the stretch from Sydenham to Bankstown will be scrapped, with the money diverted to the West Metro to Paramatta.