After successfully expelling visa overstayers over the past decade, Japan is now shifting its immigration control focus to a new target: people in the country on bogus visas.

Prime Minister Shinzo Abe's government has submitted a bill to revise the immigration control law that will stiffen the crackdown on individuals it views as an emerging threat to public safety.

While it is unclear whether the bill will be passed during the current Diet session that ends in late September, lawyers and activists warn it is intended to give authorities leeway to weed out foreigners they consider "undesirable."