The Diet on Thursday enacted a law that toughens penalties imposed on illegal aliens in Japan -- but expands the window of opportunity for prospective asylum-seekers.

The amendment to the Immigration Control and Refugee Recognition Law, enacted after passing the House of Representatives at a plenary session in the afternoon, raises the maximum fine for illegal aliens to 3 million yen from the current 300,000 yen.

It also doubles the period of a ban on the re-entry of foreigners deported from Japan to 10 years.