TOKYO—Japan is considering whether to allow its naval ships to join international patrols off the coast of Somalia to help fight piracy, a newspaper reported Wednesday.

The government intends to submit legislation -- spearheaded by Prime Minister Taro Aso's administration -- during parliament's current session, which ends in March, the Yomiuri newspaper reported.

There are over a dozen warships guarding Somalia's waters. Countries as diverse as the US, Britain, China, France, Germany and Iran have naval forces off the Somali coast or on their way there.

The report said some ships could be sent before the bill is passed as an emergency measure, but it did not provide details. Sending ships before it is lawful would likely bring protests from Japanese opposition parties.

Government officials were not immediately available to confirm the report, which quoted anonymous sources.

Japan's military is strictly limited to defensive activities by the country's postwar constitution. Critics say that sending ships to global hotspots could lead to problems if they come under attack or must assist friendly countries' vessels.

The government said none of its ships has been hijacked this year, but pirates fired at three Japanese vessels. No one was injured.

Pirates attacked 111 ships around the Gulf of Aden in 2008, hijacking 42 of them and earning tens of millions in ransom. Fifteen ships with more than 260 crew are still in the hands of pirates, according to the International Maritime Bureau.

The pirates have been able to operate so successfully because Somalia has not had a functioning government since warlords overthrew a dictator in 1991 and then turned on each other.