Australia's venomous redback spider, first sighted in Japan 17 years ago, is crawling toward Tokyo, with at least one of the creepy-crawlies found in a neighbouring city, officials said Wednesday.

A man in Kawasaki, which borders southern Tokyo, used an insecticide to kill a strange spider and three egg sacs found inside a sprinkler in his garden on Monday, authorities said.

City officials later confirmed the insect to be a redback, which the national government has labelled an invasive alien species deemed a menace to the country's ecosystem.

The Environment Ministry said redbacks had been found in 23 of Japan's 47 administrative districts. The district including Kawasaki is the closest the spiders have been detected to Tokyo.

"They are presumed to have spread their habitats widely in Japan as they were carried while nestling in cargo, containers, construction materials, automobiles and such" after possibly arriving by sea originally, the ministry said on its website.

"I myself feel that they have come so close," Katsutoshi Oikawa, an environmental official at Tokyo's metropolitan government, told AFP.

"We have not yet proactively worked out measures. But we have been responding to individual inquiries from citizens about ways to deal with the spiders."

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.

Hundreds of cobras seized in Thai customs bust
Bangkok (AFP) Nov 14, 2012 - Thai customs officers have seized hundreds of cobras being smuggled through the country for use in traditional medicine as a supposed sexual aid, an official said Wednesday.

The 600 deadly wild snakes were discovered in crates on a truck when it was stopped at a checkpoint in the south of the country.

"They were in blue net bags, they could breathe through the net -- there were about five cobras in each bag," the customs officer told AFP, requesting anonymity.

Estimating the total number of snakes at around 600, the officer said a full count would take place on Wednesday night as it was too dangerous to do it without extra help.

The cobras, worth an estimated $16,300, were destined to be used in traditional medicine, the official said.

They are prized in some forms of Chinese medicine, which holds that their blood and meat boosts sexual potency.

The snakes had been smuggled in via the southern Thai border and were believed to be on their way through the kingdom and destined for neighbouring countries, the official added.

There are three cobra species native to Thailand. Although none is endangered, the export of live snakes is banned under the Convention on International Trade in Endangered Species of Wild Flora and Fauna.

Two men have been arrested in connection with Monday night's haul in Prachuap Khiri Khan province and face up to 10 years in jail.

The cobras have been sent to a national park in central Thailand.

Three rare Sumatran tiger cubs born at Indonesia zoo
Medan, Indonesia (AFP) Nov 14, 2012 - A critically endangered Sumatran tiger has given birth to three cubs at an Indonesian zoo, a veterinarian at the facility said Wednesday.

"She gave birth naturally, without human intervention. The three cubs are all healthy. Two are male, while we haven't been able to get close to the other to identify it," Suci Terawan, a vet at Medan Zoo in northern Sumatra, told AFP.

The 13-year-old Sumatran tiger named Manis, or Sweetie in English, gave birth to the cubs on October 18, just over a year after she successfully bore three male cubs, Terawan said.

"This is our latest contribution in conserving the critically endangered species," he said, adding that the zoo now has six cubs, and two male and one female adult.

Earlier this year a Sumatran tiger at a zoo on the island's Jambi province gave birth to three cubs, but only two survived.

Fewer than 400 Sumatran tigers are left in the wild, conservationists say, with several dying each year as a result of traps, poaching and other human intervention.