PORT MORESBY - A passenger plane carrying 13 people including nine Australians is missing feared crashed over Papua New Guinea, the airline and Australian officials said Tuesday.

The 20-seater Twin Otter craft disappeared at 10:53 am (2353 GMT) en route to popular tourist destination Kokoda after taking off from the South Pacific nation's capital Port Moresby.

"As time passes it looks more (likely) that it will be an accident," Airlines PNG official Allen Tyson told AFP, adding that search operations were being hampered by bad weather.

Canberra's foreign affairs department said nine of the 11 passengers were Australians. Two crew were also on board the plane to Kokoda, site of a hiking trail and famous World War II battle involving Australian troops.

"Nine of the passengers are known to be Australians," the department said in a statement. "Consular staff are contacting families of the Australian passengers to offer consular assistance."

Australian Foreign Minister Stephen Smith said officials in Port Moresby were doing everything they could to find the plane but added weather conditions were making the search "very difficult."

"A search is now underway for the aircraft. I am advised that weather conditions are making that search very difficult. That search includes checks of other airfields in the vicinity," Smith told parliament in Canberra.

"The Australian High Commissioner and his officers in the Commission in Port Moresby are now urgently liasing with Port Moresby authorities to do everything they can to determine the whereabouts of the aircraft."

Airline official Tyson said helicopters and other aircraft were combing the rugged Owen Stanley Range north of Port Moresby.

"Bad weather is hindering the search and rescue into the area so at this stage we still can't confirm whether it's an accident or if the aircraft has potentially landed elsewhere and is unable to contact us," Tyson said.

"We have a number of helicopters and fixed-wing aircraft in the area trying to find the aircraft so at this stage we're still unable to confirm whether it is actually an accident."

At least 19 planes have crashed since 2000 in Papua New Guinea, whose rugged terrain and lack of internal connecting roads make air travel crucial for its six million citizens.

Australian pilots died in crashes in PNG in July 2004, February 2005 and October 2006.

Reports that corruption and a lack of funding had led to a sharp decline in safety standards prompted the establishment of an air accident investigation commission last year.