Virginia Gov. Mills E. Godwin, in a surprise move, announced yesterday that he has vetoed legislation that would have required more than 500 of his political appointees and members of the utility-regulating State Corporation Commission to fill out the state's limited personal financial disclosure forms.

The governor said the bills, among the major victories claimed by Common Cause of Virginia during the recent legislative session, would have forced unpaid board and commission members to undergo "an invasion of privacy beyond reason or logic."

His action caught supporters of the legislation by surprise. "I am truly outraged at the tactics the governor followed in this matter," declared State Sen. Joseph V. Gartlan (D-Fairfax), sponsor of the bill that would have affected gubernatorial appointees.

Gartlan was not the only legislator angered by Godwin's last-minute decisions to kill bills passed by the 1977 General Assembly. In all, Godwin vetoed 34 of the 719 bills passed by the legislature, his office announced.

Among the final bills Godwin vetoed before his Sunday midnight deadline were measures that would have allowed druggists to sell prescription drugs in bottles without a so-called "childproof" cap and would have required law enforcement agencies to see that a central criminal records bureau is advised of the outcome of any criminal charge the agency brings.

Some of the vetoes had been expected since Godwin two weeks ago had listed eight bills that he was likely to veto. But the disclosure bills were not on the list and Gartlan said yesterday he did not learn until 4:30 p.m. Sunday that his bill was in trouble.

That was "less than eight hours" before the midnight deadline and not enough time to mobilize the citizen Common Cause supporters who had helped push the bill through the legislature, Gartlan said.

The bill had passed the Senate without a negative vote and had won narrow approval in the 100-member House of Delegates - which Gartlan said indicated wide support for the bill. "To ignore that is to take a head-in-the-sand attitude," Gartlan said.

Under terms of Gartlan's bill and a similar one sponsored by Sen. Virgil H. Goode (D-Franklin), state and SCC employees involved in financial dealings, along with about 500 gubernatorial appointees to state boards and commissions, would have had to complete a conflict-of-interest disclosure form. The form would have been similar to one required of the 140 legislators, as well as Godwin, the lieutenant governor and attorney general.

Although the form requires only a generalized listing of a person's economic holdings and income, Godwin said it would pose "an unwarranted restriction on the private lives of public servants." Under a House amendment to the bill, Godwin would have been able to exempt any of his appointees from the requirements that they complete the form.

"The attorney general advised me that these bills are unnecessary in the light of the current conflict-of-interest law and that they could have a deleterious effect on the ability of the state to procure the services of highly qualified and respected members of the community," Godwin said. Attorney General Anthony F. Troy said current gubernatorial appointees are covered under the existing law, although the financial disclosure is not mandatory.

Gartland and other supporters of the disclosure bills had argued that they were needed to restore public confidence in state government and were similar to measures enacted by many other states. The supporters contended that the disclosure requirements would not deter people from accepting unpaid positions on state boards and argued that the board members often exert more power than legislators in the approval of state contracts.

Maryland Gov. Marvin Mandel, by comaprison, last year vetoed 90 of 1,098 pieces of legislation passed by the Maryland legislature. His vetoes are automatically considered at the opening of the next legislative session.

Godwin's 34 vetoes, although less than the 42 he issues in 1976, are expected to help build pressure on the legislature for a veto session at which the Virginia legislature could consider overriding the governor's actions. Legislation providing for such a session was approved this year, but will have to be approved again next year, and then by the public, before it can become effective in 1980.