Inner Sydney councils are requesting better facilities for walking and cycling as well as extra train stations as part of the Baird government's $12 billion metro line through central Sydney.

In submissions to the project, which will connect to the $8.3 billion Sydney Metro North West at Chatswood and join the existing Bankstown Line at Sydenham, councils urged the government not to waste the opportunities created by the new line.

The City of Sydney Council and the Inner West Council are pushing for an extra station to be added near the Ashmore estate development at the border of Alexandria and Erskineville.

Apartments will be built for about 6000 residents in the former industrial precinct at Ashmore in the next decade. But there are no rail stations planned for the area, because of the gap of about four kilometres between a proposed Waterloo stop and Sydenham.