A majority of the Prince William County Board of Supervisors said yesterday the issue of whether to switch to an urban county executive form of government needs more study, rejecting a bid by some board members who wanted the question sent to a voter referendum without delay.

Confronted with Prince William's massive growth and the resulting strain placed on county services, the board has been wrestling intermittently with changes in its form of government because it wants the authority to raise and spend money on roads. Although the board delayed taking definite action yesterday, board members conveyed a strong interest in presenting voters with the option of a new form of government in this fall's election.

An urban county executive form of government, the most widely discussed of these options, would give Prince William an elected countywide board chairman. It also calls for levying personal property taxes on a pro-rata basis and two-year instead of four-year terms for School Board members.

It allows the possibility of increased county authority to raise and spend money on roads, similar to the powers that cities hold under Virginia law. But a second referendum would be needed to acquire this power.

The idea of an elected countywide board chairman has been gaining increasing momentum on the board. At a meeting two weeks ago, the board endorsed a measure initiated by state Sen. Charles J. Colgan that would give the county authority to make such a change.

No General Assembly approval would be required, however, if voters elected to switch to an urban county form of government in a fall referendum, according to County Attorney John Foote.

Yesterday's action calls for a board work session devoted to possible changes in Prince William's government and directs the county staff to provide details of the specific costs and benefits of a switch to urban county status.

Some board members were eager for more decisive action.

"I don't want to know any more information," said Supervisor Donald E. Kidwell. "I think we know what the different forms of government allow us to do."

Kidwell, joined by supervisors Guy A. Guiffre and Joseph B. Reading, tried unsuccessfully to put the urban county government issue on the fall ballot immediately.

Kidwell lauded the urban county measure that would allow the county to prorate property taxes. Under current law, Prince William residents do not pay tax on property until the start of the year after they buy it. By the same token, people who sell property must pay tax on it for an entire year rather than the portion during which they own it.