Virginia Gov. John N. Dalton vetoed a bill yesterday providing for party labels on state election ballots because he said party affiliation is not as important as a candidate's "character, capacity philosophy and leadership."

The party designation bill vetoed by the Republican governor had been passed handily by both houses of the overwhelmingly Democratic General Assembly. Out of 44 vetoes announced by Dalton, it was one of only a handful that involved deep policy difference between the assembly and the governor.

Other vetoes killed bills expanding teacher rights in firing and probation cases, giving optometrists the right to administer eyedrops and other drugs, shifting control of lobbyist registraion from the administration to the Senate clerk, obligating the state to pay city and county welfare administration costs in 1980 and prohibiting inmates on work-release programs from working for employers being struck by unions.

Some of these vetoes are likely to spur the campaign for approval by voters of a constitutional amendment that would enable the assembly to override vetoes handed down after the assembly adjourns. Such an amendment has been proposed and will be on the general election ballot next Nov. 7.

If the proposed amendment is approved by a majority of voters then bills passed during next year's legislative session and vetoed after adjournment can be reconsidered by the legislators in a second session six weeks after the regular session ends. A two-thirds vote of both the Senate and House of Delegates is required to override a vedo.

Party designation on ballots long has been a goal of the Democratic State Central Committee, but until his this year bills providing for it have been defeated largely on the strength of opposition from conservative Democratic legislators leery of too close an identification with more liberal national Democrats.

It also has been opposed by many Republicans who fear that party labels on ballots in a traditionaly Democratic state would be a disadvantage to them.

Under existing election laws, only presidential candidates are designated by party in Virginia. This led to voter confusion in 1978 because the ballot that year placed U.S. Senate and House candidates, who were not labeled by party, in columns beside presidential candidates running under party labels.

Dalton's veto of the party designation bill was accompanied by a statement strongly suggesting that party identification does not mean much in Virginia.

"This bill attempts to promote party labels as a main criterion for voting," he said. "While the voters show an increasing interest in supporting candidates who are in harmony with their views regardless of party, this bill attempts to focus attention at the last possible moment prior to voting, on a party label. The label cannot hope to encompass the great variety of things that go to make a good public official.

"A party label is not as important as the candidate's character, capacity, philosophy and leadership. This bill is at odds with our Virginia tradition, which holds that the good of the commonwealth is far more important than the transitory good of any political party."

Of the 44 Dalton vetoes, 21, he said, eliminated legislation duplicated by other bills that he signed into law. The rest killed bills that he said he objected to for technical or policy reasons. He signed 850 of the 894 bills passed by the assembly.

Two vetoes killed bills that were major legislative goals of the Virginia Education Association, the principal organization representing public school teachers throughout the state.

One of these would have provided for a fact-finding panel to advise city and county school boards on proposed dismissals and probation of tenured teachers. Tenured teachers are those who have served beyond their three-year probationary period.

The other would have required school boards to hold hearings on demotions of supervisors and principals to lower paying teacher jobs.

Dalton's vetoes of these immediately were criticized by VEA president Mary Hatwood-Futrell.

"It is very unfair of the governor to veto fact-finding panels for teachers after signing a bill that gives other state employes the right to a hearing before a fact-finding panel that can make a binding ruling overturning a dismissal or probation," she said.

"With respect to the bill protecting school administrators, the legislation simply would have required a hearing. The school boards would retain full authority for final action under both bills. They would not have 'usurped' board authority, as the governor suggested," she said.

Hatwood-Futrell said the VEA will seek passage of both bills again next year and will work vigorously for approval of the override amendment.

The bill permitting optometrists to use certain drugs that sometimes have lethal side effects for diagnostic purposes had been strongly opposed by ophahalmologists, physicians who treat diseases of the eyes. Optometrists are not medical doctors. Dalton said he fears the bill did not provide adequate medical safeguards.

The bill obligating the state to pick up full costs of welfare administration, now paid in part by city and county governments, would not have become effective until 1980. Dalton said he objected to it because it obligates the state to provide unspecified revenue in the future. He said the legislation should await completion of a study of the local tax impact of state programs.

He also vetoed a bill raising fees paid to court-appointed lawyers because he said the assembly did not provide the $2 million needed to fund it.

A bill giving the assembly, if it is in session, the right to rescind an emergency order of the governor was also vetoed. Dalton said it could delay federal assistance in emergencies.

Two bills signed by the governor toward the end of the 3-day post-adjournment veto period provide for greatly expanded financial disclosure by state officials and employes. One, sponsored by Sen. Joseph V. Gartland (D-Fairfax), subjects officials with discretion over state spending and judges to the same financial disclosure requirements already imposed on legislators. The other, sponsored by Sen. Wiley P. Mitchell Jr. (R-Alexandria), makes public the salaries of all state workersearning more than $10,000 annually.