Australia plans to destroy thousands of honey bees as their colonies have been invaded by a deadly parasite.   The varroa destructor was first found at a port near Sydney last week but has since been spotted in hives 100km away, according to a BBC report.

The step is being taken to prevent spread of the parasite to bees in other parts of the country. A “lockdown” has also been imposed on the movement of bees nationwide as part of the biosecurity measures to keep them safe.

Australia was the only continent free of the varroa mites, which are the biggest threat to bees worldwide.

The tiny pests weaken and devour colonies by feasting on them and transmitting viruses.

If the mites continue to spread, it could cost the honey production industry alone $70 million (USD 48m) a year, according to the BBC report.

About a third of Australia's food production relies on bee pollination, including almonds, apples and avocadoes.

Farmers expect the next few days to be critical in tackling the outbreak.