The Virginia House of Delegates today approved an end to the state's six-year ban on annexations with a controversial plan that could lead to some suburban counties funneling their tax dollars into adjacent cities.

Displaying some vote trading rarely seen in public, backers of the measure pushed it through the House despite opposition from some rural legislators. If approved by the Senate and Gov. Mills E. Godwin, the second state in the nation with a mechanism for suburban counties to give a portion of their tax revenues to central cities.

Only Minnesota currently has such a provision in its laws, said Del. Thomas J. Michie (D-Charlottesville), chief sponsor of the measure. The revenue-sharing provision, which had led Fairfax County Board of Supervisiors to oppose the bill, "is not going to save the central cities," Michie told the House. "It's just a little help."

If approved by the suburban countries around Richmond, the provision could give the capital city by 1985 as much as $2 million a year from the suburbs, he said Michie said the provision could also lead to Fiarfax County funneling revenues into Arlington, which is defined as urban county under Virginia law, and the city of Alexandria, but he said he didn't have any figures on how much money such as agreement in Northern Virginia would involve.

Under the provisions of the bill, so complex that some legislators said after the vote today they were not certain of the bills impact, suburban counties such as Fairfax would have to contribute to neighboring urban areas only if they seek to become immune from annexation by the surrounding localities.

In Virginia cities and counties are separate and distinct jurisdictions and cities are allowed to annex portions of surrounding counties only after making a court aproved awared to the county for its loss of taxable property.

Passage of the measure by a voice vote came after Michie agreed during a debate to trade off with Del. Richard W. Elliott (D-Campbell), a leader of the opposition.

Breaking with the House's traditional, stilted debate style, Michie exclaimed, "I'll buy it" when Campbell offer to support the bill if it were to contain a limit of one annexation every 10 years by cities.

With that, much of the rural opposition to the measure died and the bill was finally approved by an overwhelming voice vote. The bill will come up for final House approval Thursday, but no debate on the measure is expected under the House's rules.

The House, with little debate, also approved today a new formula for distributing highway construction funds among the state's localities. Sponsors of the measure sadi it would give every jurisdiction more funds, but the largest individual increase under the new formula would go to Fairfax County, which would gain an additional $514216 this year for its secondary roads system under the new formula. After a final vote Thursday, the roads measure will be sent to the Senate.

In urging passage of the annexation measure Michie conceded that the bill might need further refinements and said its provisions would not become effective until mid-1973 so it could be annexed next year.

Under provisions of the bill nine Virginia counties - inlcuding Fairfax. Arlington and Prince William in Northern Virginia - could qualify to become immune from annexations. If the counties did not seek immunity, Michie said the bill would have "no effect at all" on them.

Fairfax County has successfully defended three annexations suits in the past 10 years and the county might be reluctant to seek immunity under the bill. Del. Raymond Vickery (D-Fairfax) said today. However, County Board Chairman John F. Herrity earlier this week voiced fears that Fairfax City may want to annex a portion of the county near Interstate Rte. 66 in an effort to capture the sales and propety tax revenues of a major shopping mall planned there.

If Fairfax County were to seek immunity, it could, under the bill's provisions block the formation of new towns in the county, such as one often discussed for the community of Reston, near Dulles International Airport. However, the bill's provisions would not block any existing town in the county, such as Vienna from later seeking city status.

In approving the measure, the House rejected a move by Del. Carrington Williams (D-Fairfax) to cut the required population for any new city to 10,000 from the bill's required level of 20,000. Current law requires a city to have a population of only 5,000 and Michie said the higher limit is needed to prevent counties from being destroyed piecemeal by the incorporation of new, small cities.

The formula for revenue-sharing for central cities is a complex one that would involve establishment of a "economic growth sharing fund" to which a city and suburban localities would contribute. Proceeds from the fund would be disbursed under a formula that takes into recognition the city's poverty, taxing rates and population.

In another legislative development today a bill introduced by Del. James M. Thomson (D-Alexandria) that would give local government and school boards the option to negotiate contracts with public employees seemed doomed to die in the House Committee on Labor and Commerce.