In an attempt to allay concerns from commuters,the government says express bus services between the north west and central Sydney via the M2 motorway will be maintained.
Transport for NSW secretary Rodd Staples said the changes to the bus network in the north west would be progressively rolled out following the opening of the new rail line.
"What we're going to do with customers is give them a bit of time to adjust. So when that service starts running on day one,people can keep doing what they're doing now in terms of buses,"he said.
However,Mr Staples said the public could expect,over the longer term,fewer buses running directly from suburbs such as Rouse Hill directly to the central city;instead,more of them would be focused on providing a link to the metro train stations.
The prospect of trains running along the rail line every four minutes during peak hours was"ideal for interchange"because it meant passengers would not be left waiting on platforms for long periods,he said.
"For some people,there will be more interchange than maybe what they've been used to. But at the same time,they are not running on a motorway where there's risk of traffic congestion,"he said.