Zoo keepers also had to wade through a deluge of water to rescue koalas. (Supplied)

Aussie zookeepers have been forced to use brooms to hold alligators inside their enclosures as floodwaters surged.

The Australian Reptile Park on the NSW Central Coast has closed after its worst flooding for 15 years.

As the waters rose in the alligator enclosure, one keeper was filmed trying to push one of the creatures away from the fence with a broom.

Zoo keepers also had to wade through a deluge of water to rescue koalas.

It's a dramatic change in weather for the park.

Director, Tim Faulkner, said it was "incredible."

The Australian Reptile Park on the NSW Central Coast has closed after its worst flooding for 15 years. (Supplied)

Left: A broom is used to fend off an alligator and right, a wet koala. (Supplied)

"Just last week, we were having daily meetings to discuss the imminent threat of bushfires, just 8km away from the Park here in Somersby," he said.