SEQ Water says it has opened all three floodgates at the North Pine dam to maintain water quality standards.

The dam reached full capacity this morning as a result of recent heavy rain.

SEQ Water spokesman Mike Foster says authorities will check to see if the water release has had an impact on fish downstream.

"[We'll] certainly be monitoring that pretty closely by Friday," he said.

"Our guys should be able to get below the dam wall safely and will be able to make an assessment of just what impact this particular release has had.

"We've certainly got some protocols in place that if we do have to undertake any fish rescues they can be done fairly promptly."