The Prince George's County House delegation today approved a bill that would grant broad new taxing powers to the county, opening the way for local taxes on such items as telephone usage and apartment rents.

The bill, which had been requested by the County Council and executive, was approved at the end of a long roll call vote of the delegates by a 13-to-11 margin. The bill called the "omnibus tax," still has to be approved by the full house and the senate before it becomes law, however, though today's action enhances its chances of eventual passage.

"Another day, another time, and I might have said that local governments should have such taxing authority," said Del. Leo F. Green (D-Prince George's) before voting against the bill. "But this only allows the county and state to avoid the major issues of comprehensive tax reform and, instead, burden our people with more nuisance taxes when they are crying for relief."

Those supporting the bill, however, claimed that the new taxes would give the county an alternative to raising the property tax rate.

"People are leaving our county because of property taxes," said bill supporter Del. Kay G. Bienan; a member of the all-Democratic county delegation. "And I promised to cut property taxes."

But even if the bill was made law, county officials said today it would not provide enough money to meet an expected budget deficit of $12.8 million. County Executive Winfield M. Kelly Jr., promised the delegation last week that he would levy only a 10 per cent telephone usage tax if the bill passes. That tax would net $4 million, far less than is needed to close the deficit, he said.

Essentially, the bill gives the Prince George's County government authority to tax anything not taxed by the state and anything that does not follow into the categories of: use of fuel or energy, differential property tax rates, intangible personal property, inheritances, insurance premiums, and most other sales taxes.

Those delegates voting in favor of the taxes were: Bienan, Andrew O. Mothershed, John J. Garrity, Perry O. Wilkson Jr., Gerald F. Devlin, David Gary Ross, Nathaniel Exum, Francis J. Santangelo S., Decatur Wayne Trotter, Craig S. Knoll, Lorraine M. Sheelhan, Frank J. Komenda, and Frederick C. Rummage.

Originally, Kelly came to Annapolis, with some fanfare, to convince the delegation to pass a "tier tax" that would restructure the real estate tax system by dividing property into three separate categories - apartments, homes, and commercial properties - and empower the county to levy separate rates on the categories.

That proposal was defeated last week. County officials, along with the delegation's subcommittee on county affairs, then decided that the omnibus tax would be the best solution to the county's problem.

After an all-day hearing Friday and a late night Monday hearing by the delegation failed to resolve the issue, delegation chairman Rummage called the 7 a.m. meeting for today, outraging the bill's opponents.

"We didn't even know they were considering the bill until last week, and then the hearing was scheduled so early we couldn't get working people to come out," said Lawrence R. Albert, of the Prince George's County Tenant Federation.

Albert, along with a representative of the Apartment & Office Building Association of Metropolitan Washington, did attend the hearing and afterwards pledged to petition for a countywide referendum to defeat the tax.

"The county, the governor, everyone says they are opposed to a tenant tax, all this bill is the tenant tax in disguise," said Albert.

An attempt by Del. Frank B. Pesci to have the omnibus tax proposal voted upon by county residents in a referendum was narrowly defeated in the delegation meeting today.