Two American alligators came within metres of freedom on Friday morning as a flash flood engulfed the Australian Reptile Park.

Dramatic video shows staff at the popular conservation zoo at Somersby on the NSW Central Coast fending off one of the giant predators with a broom as he made his way onto the interior fence of the Alligator Lagoon, buoyed by floodwaters that rose rapidly on Friday morning.

Australian Reptile park director Tim Faulkner carried two koalas over a swollen raging creek to safety from the deluge in the Australian Reptile Park video.

The park was closed on Friday as staff moved quickly to protect the animals after flood waters began rapidly rising about 7.30am.

Staff fended the large male alligator off the Alligator Lagoon's first fence with a broom

The giant predators became highly excited by the rain and rapidly rising floodwaters

An alligator looks out to freedom. The floodwaters rapidly rose beyond the first fence line

The biggest flood waters in 15 years quickly rose to the top of the first fence. Daily Mail Australia understands the Lagoon is guarded by two fences so they were not at risk of escape

The Bureau of Meteorology's rainfall map on Friday. Spot thunderstorms dumped heavy rain in localised areas causing hotspots of flash flooding, including on parts of the Central Coast. The wet weather is likely to continue until Wednesday

Mr Faulkner said keepers were stationed at the Alligator Lagoon to monitor the water levels, which were rising beyond the fence line.

'We haven’t seen flooding like this at the Park for over 15 years,' he said in an emailed statement.

The park's enormous alligator lagoon is home to 35 of the potentially dangerous reptiles, native to north America, which grow up to 3.5m and weigh up to 400kg.

It is ringed by two fences for safety.

Even if an alligator made it past the first fence, it is understood that it would be in no position to escape into the wild - but it would be quite difficult to catch them between the two fences and put them back in the lagoon.

A wet koala at the park enjoys the rain after months of dry weather and nearby bushfires

Australian Reptile park director Tim Faulkner acted fast to move these wet koalas to a safer area as a precaution

Australian Reptile Park staff immediately closed the park and moved the animals to safety

Floodwaters pour down a road at the Australian Reptile Park in Somersby, NSW, near Gosford

Mr Faulkner checks the soundness of a bridge barricade during the rapid flood

The Australian Reptile Park was closed Friday as staff cleaned floodwaters from the buildings

The alligators are said to have become highly excited in the rain after months of dry weather and are understood to be 'having a ball' in Friday's flood.

The waters rose so rapidly on Friday they dislodged a small dinghy which can be seen in the video crossing the Alligator Lagoon with nobody at the helm.

Fortunately, it later floated back onto shore.

Mr Faulkner said the contrast to the bushfire crisis was striking.

'This is incredible,' he said.

Workers probe the ground for hazards and inspect a flood-damaged fence on Friday

This wet koala may have been surprised by the sudden flood after months of drought

FACTS ABOUT THE AMERICAN ALLIGATOR - Males grow to an average of 3.4m and can weigh up to 454kg - Females grow to an average of 2.6m - Carnivorous reptiles native to the USA and found from North Carolina to the Rio Grande in Texas - They eat fish, turtles, birds and mammals that come to the waterline - Live in fresh water favouring slow rivers, marshes and swamps - Cannot tolerate salt water for long - Live about 50 years in the wild - Deemed not as deadly to humans as Australia's native saltwater crocodiles - Are smaller than saltwater crocodiles - Have wider, U-shaped snouts than saltwater crocodiles which have more pointed, V-shaped snouts Source: Smithsonian's National Zoo & Conservation Biology Institute Advertisement

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

Mr Faulkner said the staff are aware that the bushfires are still burning and the rain doesn't replace the millions of hectares of lost animal habitat.

The Australian Reptile Park works to protect native animals including the bushfire survivors through its conservation charity Aussie Ark.

He had just returned from a mission to the drought-shrivelled creeks in the Barrington Tops area to rescue endangered Manning River turtles and platypus when the flash flood suddenly struck on Friday morning.

On Friday, staff at the park were busy mopping out the offices and display areas, and checking all the enclosures, repairing any damage.

Mr Faulkner said the staff's quick action had got the flooding under control and he said he expected the park to reopen on Saturday.

'We’ll be open and ready to welcome visitors for the rest of the summer school holidays,' he said.

Bureau of Meteorology duty forecaster Neale Fraser said 30mm to 40mm of rain had fallen quickly on Somersby and surrounding Central Coast areas from about 7am to 8.30am on Friday causing some localised flooding.

'There were showers overnight but they intensified with thunderstorms for about an hour,' he told Daily Mail Australia.

'Things are so dry it's (the water) probably running off rather than soaking in.'

Mr Fraser said the Central Coast could expect lighter showers today and tomorrow.