Taxes on marijuana would hit to 28 percent under the bill Massachusetts House lawmakers plan to propose and take up this week. A legalization advocacy group called the tax hike "irrational" and a boost to the black market.

The House proposal's tax increase is a steep spike from the 12 percent total in the current law approved by voters in November. The voters' law broadly legalized marijuana use for adults age 21 and over.

The House bill is expected to emerge at a committee meeting on Wednesday at noon on Beacon Hill. House lawmakers could vote on the bill Thursday.

MassLive.com on Tuesday evening obtained a copy of the legislation, which also revamps the cannabis control commission created under the voter-approved law, expanding it to five members from three, and giving the governor and the state attorney general the power to appoint some of its members, in addition to the state treasurer having a say in appointments.

Marijuana is still illegal at the federal level.

The House bill also touches on medical marijuana. Under the House bill, the state Department of Public Health would lose oversight of medical marijuana. House lawmakers are seeking to hand over the oversight to the commission.

Medical marijuana would still be untaxed.

Massachusetts voters approved marijuana for medical use in 2012, and state officials were slow to implement the law.

But lawmakers are now moving quickly to overhaul the November 2016 law voters endorsed.

The House bill allows for up to 12 plants per household, same as the voter-approved law, and possession of up to an ounce.

But the bill seeks to put in place strict limits on advertising and marketing marijuana products.

The bill allows to Massachusetts cities and towns to block aspects of the marijuana law through a vote of the city council and approval of the city or town's chief executive, like a mayor or town manager, rather than the referendum process laid out in the voter-approved law.

House lawmakers crafted the bill behind closed doors. On Tuesday afternoon, nearly 24 hours before the Legislature's Marijuana Policy Committee was scheduled to meet, the chair of the committee's Senate side, Patricia Jehlen, said she hadn't seen a copy of the bill.

The House chairman of the committee is Mark Cusack, D-Braintree.

The Massachusetts Senate will likely seek its own changes to the law before lawmakers from both the House and the Senate work out differences and send a bill to Gov. Charlie Baker's desk.

Marijuana advocates had urged House and Senate lawmakers to hold off on any changes until the new industry was up and running in Massachusetts.

The group behind the 2016 voter ballot question legalizing marijuana on Tuesday night panned the House proposal, saying it in "no way improves the measure passed by voters."

"It weakens it and it insults voters in the process," the group, "Yes on 4," said in a statement. "Its irrational tax increase will give drug dealers the ability to undercut the legal market, and its removal of ban authority from local voters will give a handful of selectmen the ability to overrule the opinion of their own constituents."

The group expressed hope that the Senate will put forward a better proposal.

"The House proposal not only disrespects the will of the voters," Jim Borghesani, spokesman for the group, told MassLive.com in an email. "It disrespects the members of the marijuana committee. Our understanding is that Senate members had no idea what was in the bill before it became public. This is Massachusetts lawmaking at its worst."

Massachusetts lawmakers and Gov. Charlie Baker have already made changes to the voter-approved law: In January, they signed off on a six-month delay on retail pot shops, pushing the date to July 2018.