SINGAPORE (AFP) - Japan's defence minister on Saturday disowned remarks by an outspoken Japanese mayor who said "comfort women" forced to provide sex during World War II were a military necessity.

The administration of Prime Minister Shinzo Abe "never commits to such remarks or recognition of history", Mr Itsunori Onodera told an Asian security conference attended by nations invaded by Japan during that war.

Osaka Mayor Toru Hashimoto prompted outrage at home and abroad by suggesting in May that battle-stressed soldiers during World War II needed the services of up to 200,000 sex slaves from Korea, China, the Philippines and elsewhere.

"In the past, Japan caused tremendous damage and suffering to the people of many countries, particularly to those of Asian nations," Mr Onodera told the security forum in Singapore known as the Shangri-La Dialogue.

"Consecutive Japanese governments have humbly acknowledged such historical facts, expressed deep remorse and genuine apologies," the minister added.

The Osaka mayor has cancelled a trip to the United States after US officials denounced his remarks as "outrageous and offensive".

He also retracted advice he gave to US military commanders in Japan that they should let their troops use licensed sex businesses as part of what he called a crime reduction strategy.