Venomous redback spiders are on the march in Japan, where they are believed to have arrived years ago as stowaways on cargo ships, a wildlife expert has warned.

The creepy-crawlies, named after their fiery markings, have infested the Osaka region and are drawing closer to the capital Tokyo, said Japan Wildlife Research Centre official Toshio Kishimoto.

A dozen people have reportedly been bitten in Osaka prefecture alone, media reports say, including a six-year-old boy who was treated with antivenom in June, the first time the medication had been used in the country.

"Their poison is strong and they are particularly dangerous to people in weak physical condition, like children and the elderly," Kishimoto told AFP.

"Redbacks are becoming a common species in Japan. They are very numerous, especially in the western region, and are now often sighted in residential areas.... Once the spiders spread, it's hard to eliminate them."

Redback bites, which inject a potent neurotoxin, have caused numerous deaths in Australia, although an antivenom stocked in hospitals has prevented fatalities more recently.

Redbacks were first spotted in Japan in 1995, around Osaka, a major port where, experts believe, they may have arrived in a container of Australian woodchips used to make paper in Japan.

Several years ago a major redback infestation was found in the street drainage system of the city, and the arachnids have now spread to prefectures covering roughly a third of the country.

In one case, a man moving from Osaka north to the Tokyo region by car unknowingly took a redback spider with him after the animal had latched onto the vehicle, the wildlife researcher said.

He said Japanese people must become more aware of the dangers of redbacks, a species long feared in Australia, where the creatures are known to lurk in garden sheds, in shoes left outdoors, and under toilet seats.

"People need to be warned on how to treat them, and to be careful when they're out cleaning ditches, and to wear thick cotton gloves for example," said Kishimoto.

Most popular

Medical student in horror gas explosionA doctor in training remains in a critical condition after an explosion in his Wangaratta unit.

Son lured his mother to her death: courtA mother was lured to her murder by a son she loved, a South Australian court has been told.

First-day employee foils armed robberAn attempted armed robbery ended in comical fashion last week when a trainee employee told the gunman he didn't know how to open the cash register.

Obsessed teacher took her top off for boyA British teacher who took her top off in front of a 15-year-old boy she was obsessed with is facing jail.

Darwin man fined over sex at petrol bowserA Darwin man busted having sex at the bowser at a petrol station has walked free from court.

Daughter 'misses' mum she killedA British woman who brutally murdered her mother two years ago now wishes she was still alive.

Kerr rules winter collection catwalkMiranda Kerr ruled the runway at David Jones' launch of the Autumn/Winter 2010 Australian designers' collections - even directing the snappers in the media pit.

TV reporter's stalker had more victimsUS prosecutors say the man who stalked a cable TV sports reporter and shot nude videos of her through a hotel room peephole also videotaped 16 other women.

Teen, 15, drove mum's car in fatal crashSydney police are trying find out how a 15-year-old unlicensed driver was able to get behind the wheel of his mother's car and cause a fatal accident.

Man dies after fall from rooftop poolA young Sydney man has died after falling over a rooftop terrace wall and plummeting two floors during an early morning swim, police say.