Environment Minister Shinjiro Koizumi has expressed support for enabling married couples to use different family names, a major break with Japanese tradition, after a ruling party lawmaker's heckling in the Diet brought the contentious issue back into the spotlight.

"I want to create a society in which people can live based on their own values. I'm positive about giving (couples) such an option," Koizumi said at a news conference Friday.

"It's quite often the case in Japan that simply offering an option sparks the kind of stiff resistance you'd expect to abolishing the existing system," said Koizumi, widely touted as a potential future prime minister.