Sentinels stand guard around Hobart's ports watching, waiting and collecting pollen.

No, they are not looking for White Walkers; they are keeping watch for bee pests and pest bees.

The sentinels are European honey bees, stationed in hives within 600 metres of ports as part of a national program to keep pests like the varroa mite out of the country.

"They're protecting other bees, they're protecting fruit and vegetables," said Karla Williams from Biosecurity Tasmania.

"We are the last bastion of healthy bees in the world."

Varroa destructor, or varroa mite, originated in Asia in Asian honey bee hives.

Since the 1960s it has spread across the globe, with Australia the only major honey-producing country still free of the pest.

Ms Williams coordinates the National Bee Pest Surveillance Program in Tasmania.

The program places working honey bee hives close to ports which beekeepers then regularly test to see if any pests or exotic bees have hitched their way in on a ship.

"The hives are tested every six weeks for all the exotic pests that we want to keep out of Australia," Ms Williams said.

Karla Williams installing a beehive at the ABC in Hobart as part of the Bee Force protection program. ( ABC Radio Hobart: Carol Raabus )

"We've got sentinel hives around the ports around Hobart, Bell Bay, Devonport and Burnie.

"It's a barrier, an early warning system."

The program also sees catch boxes placed around ports — empty hives designed to attract bee swarms that might have stowed away on a visiting ship.

Peter Norris, the president of the Southern Beekeepers Association, takes part by regularly testing his hives kept at the Royal Tasmanian Botanical Gardens.

"It's absolutely crucial that varroa doesn't hit Australia, especially Tasmania," he said.

"I was an amateur beekeeper in the UK when it hit over there and we lost 80 per cent of the bees in the south of England in the first year it was there.

"We're very lucky here in Tassie, we're pretty pest free at the moment."

Because of the lack of varroa mite and other bee pests such as the small hive beetle, which has been found in other parts of Australia, Tasmania's bees are a sought-after commodity.

Each year Tasmania exports bees to Canada and the United States where thousands are lost over the cold winter months and to varroa and other pests.

This makes the job of the sentinel bees not just important for the state but for the world.

Ms Williams said they were keen to hear from beekeepers to "bee-come" part of the program, which can be done via the Biosecurity Tasmania website.