The US Senate Committee on Appropriations has approved a bill to establish regulated marijuana stores in Washington, D.C. and allow banks to provide financial services to recreational or medicinal marijuana manufacturers, producers or sellers in states where it the drug is legal.

"None of the funds made available in this Act may be used, with respect to a State where marijuana is legal for recreational or medicinal purposes, to prohibit or penalise a financial institution solely because the institution provides financial services to an entity that is a manufacturer, producer, or a person that participates in any business or organised activity that involves handling marijuana or marijuana products; and engages in such activity pursuant to a law established by a State or a unit of local government," according to the Senate amendment passed by the committee.

"Meanwhile sentencing reform is gaining steam, and the US is shifting towards treating drug use as a health issue instead of a criminal justice issue," according to a Huffington Post's blog.

About 23 US states have already legalised marijuana for medical use while 16 others have legalised cannabidiol oil, a derivative of marijuana that is used in treating epilectic seizures in children.

"The stage has been set to end the federal government's failed war on marijuana," said Michael Collins of the Drug Policy Alliance.

About 72 percent of Washington, D.C. voters approved last November a ballot to legalise the possession and growing of marijuana for personal use.

The amendment is included in the Financial Services spending bill. If it becomes a law, D.C. could regulate marijuana from labelling, age restrictions and taxes.

The alliance said marijuana businesses operate on a cash only basis.

Last year, the US House voted to allow states to set their own marijuana policies while a marijuana amendment was signed into law also last year.