The animal has tested positive to the Australian bat lyssavirus, which can cause serious illness in humans and has killed two people since it was identified in 1996.

The men were all attacked by the 'little red flying fox' while walking separately along a track at Joseph Banks Conservation Park near the Township of 1770, south of Gladstone..

Australian bat lyssavirus is one of seven types of lyssavirus which are found around the world, according to a Queensland Health fact file.

Another type of lyssavirus is the potentially fatal rabies.

The men - two of whom were visitors to the area - have returned to their homes in Ipswich, Hervey Bay and Agnes Water while a course of post-exposure prophylactic treatment and counselling are arranged.

''The bat swooped down and bit each of the men on the head or ears,'' acting chief health officer Christine Selvey told reporters.

"There is a risk the virus can be transmitted to humans, however we have a very highly effective treatment regime.

"If it's not correctly treated then the virus can spread along the nerves to the brain which causes an infection of the brain which would be fatal.''

The bat was killed by the third victim and then taken to Queensland Health's Coopers Plains lab for testing.

Biosecurity Queensland's principal veterinary scientist Janine Barrett said the Australian bat lyssavirus was carried by less than one per cent of the bat population, and passed on from animal to animal by scratching or biting.

Queensland Health figures show five bats tested positive to Australian bat lyssavirus last year.

Dr Selvey said the only two known cases of Australian bat lyssavirus in humans were in the 1990s.

Both were fatal.

''Since then we have introduced routine prophylaxis for bat bites and scratches and there have been no further cases,'' she said.

Anyone attacked by a bat is urged to contact medical authorities.