Australian maritime authorities are being stretched by efforts to patrol thousands of miles of ocean around the Cocos Islands, the latest territory targeted by asylum seekers.

Since the middle of May, three boats carrying 135 asylum seekers have arrived at the Cocos, lying about halfway between Australia and Sri Lanka, a report by The Age newspaper said.

Many asylum seekers pay thousands of dollars to smugglers for passage on rickety boats destined for waters closer to Australia, mainly around Christmas Island, south of the Indonesian island of Java, or around Ashmore Reef off West Timor.

By heading for the Cocos Islands, the asylum seekers are forcing Australia's coast guard to sail thousands of miles more a month to fulfill duties to patrol Australian waters but also to help people in danger on the high seas.

More than 4,000 people have risked a boat journey to Australia this year -- almost the same number as for all of last year, The Age report said.

Another two boats carrying 150 people recently were intercepted off Christmas Island.

The Cocos, or Keeling, Islands are around 1,500 nautical miles northwest of Perth.

They were first seen by Europeans in the 17th century by British Capt. William Keeling of the East India Company. The British annexed the Cocos in 1857 and handed over to be administered by Australia in 1955.

The islands -- less than 6 square miles -- consist of two primary flat coral atolls averaging around 16 feet above sea level and up to 27 coral islands.

The Cocos lie around 1,620 nautical miles from Sri Lanka where many asylum seekers begin their sea journey to Australia.

Sri Lanka's high commissioner in Canberra, Thisara Samarasinghe, told The Age that Sri Lankan security services recently picked up 113 people on a boat destined for Australia.

''Our information is people are being paid by various organizations to come (to Australia),'' Samarasinghe said. ''It's a very international racket for the purpose of collecting money."

Australia is the main destination of choice for the asylum seekers.

Thousands of those who set sail make it but find they await months in crowded detention centers, the main one being on Christmas Island, before their case is heard.

Also, hundreds of those who set sail -- including children -- don't make it.

One of the worst sinkings happened in December when around 200 people, including dozens of children, apparently drowned. Their overcrowded wooden ship carrying up to 400 asylum seekers wrecked about 25 miles off the coast of Indonesia's Java Island.

The passengers, mostly from Afghanistan, Iraq, Iran and Turkey, reportedly paid $2,500-$5,000 to people-smugglers for illegal passage to Australia where they would claim asylum.

Australia's government insists the asylum problem is a regional one because the people smugglers operate out of Indian Ocean countries including Malaysia, Indonesia and Sri Lanka.

To ease the pressure on Australian detention centers, Canberra has been trying to seal agreements to set up and help operate centers with the Micronesian island of Nauru, at 8 square miles the world's smallest republic, and Papua New Guinea.