Travellers returning from a summer break in Bali during the peak holiday period have been warned to expect unprecedented airport security screenings.

The warning – which also applies to Australians visiting other South-East Asian destinations – comes as the country bolsters its defences against a devastating outbreak of African swine fever (ASF).

The crackdown will involve about 130 extra frontline biosecurity officers, who will do half a million more passenger screenings a year.

Arriving passengers can also expect extra questions from officers, as well as ramped-up audio and video warnings on all flights.

There will also be more sniffer dogs and X-ray machines at airports across Australia over the summer, as part of a $66 million package to protect the country’s $5 billion pork industry.

Airports of particular focus include Cairns, Sydney, Melbourne, Perth, Adelaide, Brisbane and Darwin.

The disease is on Australia’s doorstep after being detected in many South-East Asian countries, including Cambodia, East Timor, Indonesia and Vietnam. It kills about 80 per cent of the pigs it infects but isn’t dangerous to humans,

Authorities are particularly concerned about travellers returning from the Indonesian island of Bali, which is a perennial favourite with Australians and home to many domestic pigs.

Other preferred destinations that are likely to attract increased security attention include Bangkok and Singapore.

“Summer is when our ports, airports and mail centres are busiest, but this holiday season will require extra vigilance from everyone as ASF is spreading,” Agriculture Department biosecurity head Lyn O’Connell said.

Darwin airport has a new sniffer dog, he’s called Lester.

He’ll be keeping a keen nose on travellers from Indonesia after African swine fever was confirmed in the country

Lester has already sniffed out 13 biosecurity risks in the last few days, including one pork product pic.twitter.com/fh1CoUPb97

— Daniel Fitzgerald (@danielpfitz) December 18, 2019

Australians arriving home from overseas must declare any goods and activities, or risk heavy penalties and fines, she warned.

“If you’re going overseas, think hard about what you bring back and if you visit a farm or go off track to a rural area, declare it when you come home and avoid bringing high-risk products in your luggage and remove potentially contaminated soil on your shoes and camping gear,” she said on Monday.

Travellers who provide false or misleading information may receive a $420 fine or face civil or criminal charges.

A Vietnamese woman was deported in October for failing to declare more than 4.5 kilograms of pork in her luggage, along with squid, quail and eggs.

-with AAP