Japan has passed a bill to legalize cannabis-based medicines in a landmark revision of its stringent drug laws, while toughening its ban on recreational use of marijuana.

The changes to Japan's cannabis and narcotics control laws passed on Wednesday in the upper house will pave the way for the lifting of a ban on medical products derived from cannabis.

Cannabis-based medicines, produced with the active ingredient cannabidiol, or CBD, are already used overseas to treat various conditions like severe epilepsy.

This is a win for patient groups that have campaigned for access to these medicines.

However, the changes amount to a tightening of Japan's already tough cannabis policy.

Marijuana consumption was criminalized, closing a loophole that officials partly blame for a recent rise in cannabis-related arrests.

Prior to the revisions, inhaling marijuana had been technically legal, as opposed to a jail term of up to five years for possession.