A builder set off an explosion after pulling a trip wire at a construction site in southeast Queensland.

The builder reportedly saw a fishing line running across the site at Ipswich, west of Brisbane, as he arrived for work on Wednesday morning.

He pulled the line which triggered a small explosion, the Queensland Times reports.

No one was injured.

The bomb squad was called in to destroy the device, but police say they are not sure if it was a bomb or not.

"If they can't categorically rule it out they'll blow it up, which they did," a spokeswoman told AAP.

"One component of it was possibly explosive, but until we get tests back we won't know."