The Assiniboine Park Zoo has temporarily closed its underwater polar bear viewing tunnel after the bears chewed into some of the silicone sealant around the tunnel's glass.

The zoo announced Friday that the tunnel, which is part of the Journey to Churchill exhibit, is closed for repairs for at least one to two weeks. However, officials have yet to determine the full extent of the damage.

"We didn't anticipate anything like this at all. They've been in that exhibit for now, what, 10 [or] 11 weeks without any incident of this nature," said Don Peterkin, chief operations officer with the Assiniboine Park Conservancy.

"It just shows you when you're working with live animals anything can happen at any time, and you just have to react accordingly."

Peterkin said visitors can still see the zoo's four polar bears at the exhibit's Churchill Coast area, which can be viewed from the Tundra Grill and outside the underwater tunnels.

But the harbour seals will be off exhibit for now, as staff will have to drain the tunnel's pools while the repairs are underway.

Zoo-goers will be offered a 10 per cent discount on admission until the tunnels re-open.

This marks the second hiccup at Journey to Churchill, which officially opened on July 3.

A week after the grand opening, some of the exhibit's wolves dug out of their habitat and into the polar bears' space. Staff had to reinforce the barrier that separates the bears from the wolves.

"When you open a new exhibit with the complexity that we have, you expect a few little glitches that you need to work on," Peterkin said. "This idea of the bears thinking they could eat the silicone wasn't one of them."