MANILA - The Department of Health said Wednesday the Philippines may have a hard time legalizing the use of medical marijuana because of existing regulations.

Speaking to reporters, Health Undersecretary Eric Domingo said the government could not go full blast in studying the beneficial qualities of medical marijuana as there is no law listing it as a product that may be registered with the Food and Drug Administration (FDA).

Marijuana is classified in the Philippines as an illegal drug.

Domingo said the Dangerous Drugs Board, the Philippine Drug Enforcement Agency, and the Philippine Institute for Traditional Alternative Healthcare were studying the proposal to make marijuana legal for medical use.

"Kaya lang (but) we cannot go full blast into studying the actual product kasi (because) it is not listed as registrable product with FDA at this time. Walang batas (there is no law) listing it as a registrable product,” he said.

He said government cannot spend funds to undertake research on a product that may not be registered for consumption in the Philippines.

"At this time, I think FDA will have to wait for an enabling law that will allow it to be a registrable product before we can actually consider pouring some resources into clinical researches for it,” he added.

No less than former President and now House Speaker Gloria Macapagal-Arroyo attested to the effectiveness of medical marijuana when she bared that she uses it to relieve her neck pain whenever she is in a country where it is legal to do so.

Arroyo suffers from a condition called multilevel cervical spondylosis, a condition characterized by neck pain.

• READ: Arroyo says she uses marijuana-based pain patch for cervical spine

Malacañang earlier said President Rodrigo Duterte will support any bill seeking to legalize medical marijuana.

• Palace: Duterte willing to sign any medical marijuana bill

House Bill No. 6517 or the Philippine Compassionate Medical Cannabis Act, which seeks to legalize marijuana for medicinal purposes, is pending before the House of Representatives.

The measure prescribes rules for the proper use of medical marijuana including the designation of a qualified medical cannabis physician, a qualified medical cannabis patient who shall be issued an identification card, a qualified medical cannabis caregiver, and a qualified medical cannabis compassionate center.

In December, Duterte stirred controversy by saying that he sometimes takes the substance to stay awake.

• Joke only: Duterte says he takes marijuana

Some doctors have opposed medical cannabis, saying its efficacy has yet to be confirmed. The use of medical marijuana is legal in California and some other parts of the United States, Canada, and Poland, among others.

Just last month, Thailand also approved the use of medical marijuana.

• Thailand approves medical marijuana in New Year's 'gift'