Japanese authorities are trying to identify a body found inside one of the landing gear compartments on a Delta Airlines plane flight that arrived in Tokyo from New York.

The body of the apparent stowaway was clad only in a long-sleeved, plaid shirt and jeans, police at the Narita International Airport said.

A mechanic found the man's body lying inside the landing gear compartment of the Boeing 777-200 during maintenance after Delta Flight 59 from New York landed at Narita on Sunday night, police official Zenjiro Watanabe said.

"All we know is that he must have sneaked in just before departure, because it is impossible for him to enter the storage during flight," Mr Watanabe said.

The body had no visible injuries except signs of frostbite, and the man might have died of hypothermia during the flight, Mr Watanabe said. The temperature in that part of the plane falls to about minus 58 degrees during flight.

Police are investigating the case both as an accident and a possible crime, Mr Watanabe said.

"It's quite bizarre," he said. "I've never handled a case like this before."

Delta officials were not immediately available for comment.

There have been similar cases in the past.

In 2007, a man who appeared to be Asian and in his 50s, was found dead in the nose gear wheel well on a United Airlines Boeing 747 that arrived at San Francisco International Airport from Shanghai. He too was thought to be a stowaway.