There are concerns someone may have put a shark inside a swimming enclosure at a beach in Perth’s northern suburbs, after the animal was found inside the nets.

The 1.5m shark was spotted by a shark-monitoring drone a 8.30am today at Quinns Rocks beach, shutting it down.

The shark was found swimming inside the net. (9news)

There are concerns someone may have let the shark in. (9news)

The area is enclosed with a shark net and authorities said there are no holes which could have allowed the bronze-whaler in, and the net is firmly secured to the ocean floor.

“There’s concrete blocks that hold it all down with anchors as well and there’s no way it can get over…you’d need a serious storm with waves going over,” Andrew Curry from Global Marine Enclosures said.

It took authorities several hours to free the shark. (9news)

It took divers several hours to herd the shark out before it was eventually freed.