A pair of US governors have filed a petition asking the US federal government to allow wider use of medical marijuana by authorizing doctors to prescribe it and pharmacies to provide it.

The petition to reclassify the drug was filed Wednesday by the governors of the western state of Washington and the northeastern state of Rhode Island, which are among the 16 states that have legalized use.

The current federal classification of marijuana as a Schedule 1 drug means it cannot be prescribed by doctors, putting states that allow medical marijuana use at odds with federal law.

"Sadly, patients must find their way along unfamiliar, uncertain paths to get what their doctors tell them would help -- medical cannabis to relieve their suffering," said a statement by Washington governor Chris Gregoire.

"People weak and sick with cancer, multiple sclerosis, and other diseases and conditions suddenly feel like -- or in fact become -- law breakers."

The US Drug Enforcement Agency considers marijuana to have no medicinal value and the FDA five years ago declined to approve it for medical use.

The Institute of Medicine in 1999 "emphasized that smoked marijuana is a crude that exposes patients to a significant number of harmful substances."

But Gregoire said some medical groups have since changed their minds, such as the American Medical Association which two years ago "reversed its position and now supports investigation and clinical research of cannabis for medicinal use."

Other such as the American College of Physicians, the Washington State Medical Association, Washington State Pharmacy, and Rhode Island Medical Society also support a reclassification.

Gregoire said her petition will require the government agencies to "conduct a new scientific review and analysis of recent advances in cannabis research since the last time the FDA reviewed the matter in 2006."

The FDA and DEA did not immediately answer AFP requests for comment.

The US Supreme court in 2009 struck down a bid to ban marijuana for medical purposes, after two California counties unsuccessfully argued that federal law outlawing marijuana should override Californian state law that permits the use, cultivation and possession of the drug for medical purposes.

The states that allow medical marijuana have passed laws that permit chronically ill patients with a medical prescription to use marijuana as a painkiller, providing they are properly registered.

The is typically dispensed from a specialized medical marijuana clinic.