Sydney Metro is being accused of "push polling" the public over the Sydenham to Bankstown section of the $20 billion rail line in telephone surveys critics say omit crucial information about the impact of the project.

Two companies, The Knowledge Warehouse and Newgate Research, have been conducting the surveys to test public attitudes towards the metro, which will replace the Bankstown heavy rail line.

The surveys cost $122,500 and involved more than 2800 people who live along the 66 kilometre Sydney Metro route from Rouse Hill in Sydney's northwest, through the city to Bankstown.

After establishing a respondent's attitude, the surveys present a series of statements about the benefits of the Sydney Metro.