AB Patterson College in the city's north enacted emergency protocols and turned parents away for about 10 minutes from 8.20am after receiving the threat.

Police have determined the threat was a hoax and the school has been reopened.

The development comes as police continue to track down the person responsible for online posts threatening a shooting at a school north of Brisbane worse than the Columbine massacre in the US.

The threats, posted on two social media platforms, warned of a school shooting at an undisclosed school in the Moreton Bay suburb of North Lakes this week.

Schools in the North Lakes area remain open.

Acting Chief Superintendent Chris Stream said there was no other intelligence to suggest the threats were credible, and parents could have confidence that their children were safe at school.

"Students attending those schools are safe with the current activities we are undertaking," he said.

"We take all threats of this type very, very seriously."

No specific schools were named in the posts, which also made reference to the recent shooting that killed 17 people at a school in Parkland, Florida.

Police will continue patrols of schools in the North Lakes region on Tuesday.