A light-rail line will be constructed from Parramatta to Strathfield via Sydney Olympic Park, Premier Mike Baird is expected to announce on Tuesday.

The line is one of four possible routes from Parramatta that have been under consideration by the state government for more than a year.

The expected announcement comes as western Sydney residents, leaders and advocates have grown increasingly frustrated about the delay in unveiling the selected route.

The four options were: Parramatta to Macquarie Park via Carlingford and Epping; Parramatta to Castle Hill via Old Northern Road; Parramatta to Bankstown; and Parramatta to Strathfield/Burwood via Sydney Olympic Park.