Alexandra Police is drafting a letter to its national dive squad after more power gel was found on the banks of the Clutha River near Clyde last week.

Senior Constable Graham Perkins said members of the Defence Force Explosive Ordnance Disposal team from Christchurch were called to safely detonate the material, which was the third time in as many months.

“All the parties involved have it down to a fine art now,” he said.

When Contact Energy lowers the river the power gel becomes washed up on the riverbank into a crater and poses a hazard to the public.

It was understood to be linked to the construction of the Clyde Dam 30-plus years ago, but police said they were now taking steps to have the issue resolved.

“We’re drafting up a request for the dive squad for a training exercise to see if they can find anything. They might find a cave or a crater somewhere,” he said.

Members of the public have been finding the power gel on the riverbank and police are advising people not to touch it, and report to police immediately.

Read more: EOD team called in to detonate explosive power gel