Engineers are checking a sink hole that has opened up in central Ipswich, west of Brisbane.

A drain has collapsed in Roderick Street, causing a crater about two metres wide and two metres deep.

The hole was small at first but began collapsing as authorities were inspecting the problem.

Ipswich Mayor Paul Pisasale says traffic is being diverted around the scene.

"We've had a few of these over the years, it was notified quickly, and I'd like to say to residents if you see something that doesn't look right, report it," he said.

"Because it could be the difference between a drama happening or not happening, and here's something that was reported early and it'll be fixed and we'll inspect all the other drains around there."