Recreational divers will soon be able to explore the wreck of one of the Japanese midget submarines that invaded Sydney Harbor during World War II. Australia will permit scuba diving on a trial basis on the Ko-hyoteki-class midget submarine, after getting approval from Tokyo, authorities recently confirmed.

To mark the 70th anniversary of the event — which sparked public hysteria in the city — New South Wales environment minister Robyn Parker said controlled diving would be allowed and divers can now get the chance to dive the historic site through a ballot system.

“Diver access will be on a trial ­basis, and the move is strongly supported by both the Commonwealth and the ­Japanese governments,” said Parker in a released statement. The families of two Japanese sailors, whose bodies are entombed in the wreck, have also given their permission.

The Japanese commanding officer of a flotilla of submarines cruising off the city ordered the daring raid on the night of May 31, 1942. Three midget submarines, each with a two-member crew, entered Sydney Harbor, slipped past a partially constructed anti-submarine boom net, and attempted to sink Allied warships.

The subs were detected and attacked, and two of the crews scuttled their boats and committed suicide. The third submarine tried to torpedo the heavy cruiser USS Chicago, but instead sank the converted Australian ferry HMAS Kuttabul, killing 21 sailors. The sub then eluded Allied Forces and escaped the harbor. Its fate remained a mystery until 2006, when scuba divers discovered it in 180 feet of water off Sydney’s northern beaches.

The craft is believed to contain the remains of the two crew and personal items such as samurai swords, good luck charms and board games, as well as unexploded demolition charges buried safely under sand.

“This is the most ‘successful,’ if you like, of the three submarines that did penetrate Sydney Harbor in 1942,” said Tim Smith from the Office of Environment and Heritage. “It was the only one that got in, right through the harbor, fired its torpedo and got out again. So M24 is very significant as a major player in that attack 70 years ago that really shook Sydney up.”

An exclusion zone, monitored by long-range cameras, is ­currently in place around the submarine. ­Parker said anyone caught damaging or ­removing part of the wreck would face penalties of up to AUS$1.1 million (US$1.38 million).