Suspicious package at Ipswich plant a hoax

Bomb squad officers have determined a suspicious package found at a water treatment plant at Ipswich west of Brisbane was a hoax.

The device was spotted around 3:25pm Tuesday at the Chuwar plant, with employees evacuated as a precaution.

The bomb squad determined the device, a medium-sized cardboard box, wasn't dangerous around 6:35pm

A police spokeswoman said investigations were getting underway into whether the device was a deliberate hoax.

"They (the bomb squad) don't usually continue investigations unless they believe something's been placed there deliberately, so they'll be looking further into that," the spokeswoman told AAP.