Photo shows HMAS AE1 in waters off the Duke of York Island group in Papua New Guinea. (Royal Australian Navy)

SYDNEY, Dec. 21 (Xinhua) -- The wreck of Australia's first submarine, a World War I vessel that disappeared 103 years ago during a patrol near Papua New Guinea, has been found in the waters nearby, Defence Minister Marise Payne told reporters here on Thursday.

The HMAS AE1 submarine went missing off Rabaul of Papua New Guinea's East New Britain province on Sept. 14, 1914, along with 35 crew members. It was finally located 300 meters deep, off the Duke of York Islands, in a 13th search attempt that began a week ago.

Payne said Australia's "oldest naval mystery" had been solved.

"The loss of the AE1 in 1914 was a tragedy," said Payne.

"It was the first loss for the Royal Australian Navy and the first allied submarine lost in World War I.

"The boat and her crew, who've been on eternal patrol since 1914 ... have now been found."

Photo shows HMAS AE1 in waters off the Duke of York Island group in Papua New Guinea. (Royal Australian Navy)

Efforts are being made to contact the descendants of the crew to "properly remember and commemorate their service and sacrifice," she said.

Australia's navy chief Tim Barrett said it was a significant day for the country, but it was also a "bittersweet moment."

"It's sweet in the fact that we have solved the mystery that has been lingering for 103 years. It's bitter because the purpose of this search was to find the men of AE1 and we have now done that ... these people who sacrificed much...for the service of their nation."