TOKYO—Japan plans to establish a 3,000-troop unit specializing in amphibious operations "as swiftly as possible," the defense minister said, publicly outlining details of the new unit for the first time as tensions with China continue over disputed islands.

Japan has undertaken an ambitious project to create a force similar to the U.S. Marine Corps, and Japanese Self-Defense Force Troops have been receiving increasingly frequent training from their U.S. counterparts in the past few years.

A plan to strengthen amphibious capabilities was laid out in Japan's new defense guidelines released in December. In detailing some of the specifics Sunday, Defense Minister Itsunori Onodera said the new force is expected to include units specializing in handling types of equipment currently unfamiliar to Japanese troops, such as amphibious vehicles and the V-22 Osprey tilt-rotor aircraft.

He said the new unit will likely be based on the southern island of Kyushu or in the Nansei Islands, which include Okinawa, considering its island mission. He added that Tokyo plans to negotiate with local governments to find a host community.

In discussing the need to Japanese protect islands, Mr. Onodera didn't mention China or Japan's territorial dispute with Beijing over small islands in the East China Sea.

"Our nation has numerous remote islands and islands of various sizes, and they give us the basis for our exclusive economic zone that ranks sixth in the world," Mr. Onodera told troops during a tour of Kyushu on Sunday. "That makes it important to provide defense for islands over the coming years."

An exclusive economic zone is an area surrounding a nation's territory in which it has the right to explore natural resources.

Currently, a Kyushu-based, 700-troop Ground Self-Defense Force unit is designated as a specialist amphibious unit, and it has been undergoing intensive training.

To train large numbers of personnel in a short time, Japan plans to step up exercises with the U.S. military, particularly the Marines, Mr. Onodera said. This week, troops from the two nations are finishing a seven-week amphibious exercise called "Iron Fist 2014" at Camp Pendleton in California, with 270 Japanese troops and 500 U.S. troops participating.

Mr. Onodera said Japan hopes to use training facilities to be built on the U.S. Pacific island territory of Guam as some U.S. Marines transfer from Okinawa.

Chinese Foreign Ministry spokesman Qin Gang told a news briefing Monday that the Japanese government's actions, especially in the military sphere, were being closely watched by the international community for "historical reasons."

"We hope the Japanese side will make good on its commitment of pursuing the path of peaceful development and make a contribution to regional peace and stability," he said.

Write to Yuka Hayashi at yuka.hayashi@wsj.com