Perth Airport rail link delayed further 12-months due to sinkhole

The opening of Perth's Forrestfield-Airport rail link has been pushed back to 2021 after the project was subject to flooding and a sinkhole causing delays in late 2018.

"The contractor apologised that the incident occurred," WA's Transport Minister Rita Saffioti said. "We both agreed that type of incident is not something we can have repeated in the future."

Ms Saffioti went on to promise that the delay would come at no extra cost to taxpayers. "There is no change to the project's budget," she said. "We believe this is an insurable incident”.

A review of the incident revealed a water leak, which began in September, was the cause of the sinkhole. It also caused damage to 26 metres of the tunnel, which will need to be repaired from the inside, or removed and re-built.

Ms Saffioti said that the completion of the $1.86 billion project has been pushed back to the second half of 2021.

"I'd like to have seen it delivered earlier, there's no doubt about it," she said. "It's a challenging project."

Once complete, the rail route will work its way through underground tunnels running from Bayswater Station on the Midland Line, along Tonkin Highway and Brearley Avenue, through the Perth Airport Estate and on to Forrestfield.

The route will handle around 20,000 passenger trips on the suburban rail network every day. It is hoped that the project will boost employment, residential and economic growth by encouraging transit-orientated development around the new suburban train stations at Redcliffe and Forrestfield.