The NSW government is facing pressure from western Sydney’s inundated communities to prioritise a new freeway to act as a major flood evacuation route after infrastructure officials admitted in 2019 there weren’t enough roads to escape.

Penrith and Blacktown councils are calling for a tract of land set aside 70 years ago to be dedicated to the estimated $1.8 billion Castlereagh Connection, a high priority of Infrastructure Australia that could help evacuate thousands of residents from the Hawkesbury-Nepean floodplain.

Penrith mayor Karen McKeown said the government’s focus had been on raising the wall of the Warragamba Dam by at least 14 metres to mitigate flood damage rather than investing in evacuation routes for western Sydney.

“This piece of infrastructure is critical,” Cr McKeown said after thousands of residents, including those living in Penrith, were this week ordered to leave their homes to avoid being cut off from evacuation routes by rising floodwaters during the one-in-50-year event.

“We’re now in life-threatening situations, we’ve got people in Colo, Londonderry, Agnes Banks, who are expected to evacuate to Castle Hill RSL,” she said, adding it was a 40-minute drive for some.

The government reinstated its intention to reserve the vacant bushland, which runs between the M7 at Hassall Grove and Castlereagh, in mid-2018, after a push to move the future transport link for the Bells Line of Road corridor received a major backlash over the acquisition of homes.

Cr McKeown said her council had repeatedly approached Minister for Western Sydney and Penrith MP Stuart Ayres over the potential route. Mr Ayres’ office did not respond to a request for comment on Wednesday.

Blacktown mayor Tony Bleasdale also backed the proposed freeway connection, which would run through his local government area, saying his council officers told him they had received no word from state bureaucrats recently regarding the project, and the floods were a wake-up call.