A coalition of 16 Virginia organizations today called for sweeping changes in the way the state registers voters, urging registration by mail and an end to the autonomy of local voting registrars.

The groups said that the changes, introduced as a bill in the General Assembly today, would erase Virginia's reputation of having some of the most restrictive registration practices in the nation.

The bill would "bring Virginia's registration laws into the 20th century," said Judy Goldberg, associate director of the Virginia Chapter of the American Civil Liberties Union, one of the groups pressing for the changes.

Del. William P. Robinson Jr. (D-Norfolk), who introduced the bill, told a press conference the measure is an attempt to "open up the procedure and remove artificial, bureaucratic obstacles to voting in Virginia."

He conceded, however, that the bill is certain to be highly controversial and stands little chance of being approved during the current legislative session. "I haven't really tested the climate . . . but you have to start somewhere," he said.

Studies of state voter registration levels show Virginia near the bottom, with about 60 percent of eligible adults registered, studies show. The legislature has been extremely reluctant to endorse major changes in the state's election laws, with many legislators insisting the state is well-served by its present laws and that the abuses often cited reflect isolated conditions in mostly rural counties.

Today's proposal comes after an 18-month study of the state's registration laws by a commisision appointed in 1983 by Gov. Charles S. Robb. The provisions of the Robinson bill go further than proposals supported by Robb during his State of the Commonwealth address last week.

Both the commission -- in a tie vote last month -- and Robb have declined to support mail registration.

Robinson said the commission failed to endorse some of the proposals in his bill because it "functioned under certain political restraints it could not overcome."

Groups supporting the bill include the League of Women Voters, the Virginia Council of Churches, the state AFL-CIO, the American Civil Liberties Union and the NAACP.

Robinson said he plans to talk with Robb in an effort to get him to support more proposals in the bill. "I think the governor promoted those items which he thought would have a reasonable chance of passage," he said.

Robb has indicated he would support a change in the state Constitution to allow state employes to act as registrars and to restrict the mandatory purges of voters who do not cast ballots within four years. Robb also supports a statewide system of registration that would allow voters to sign up at any registration office or during any voters' drive. Voters may now register only in their own or adjacent jurisdictions.

In his 1981 gubernatorial campaign, Robb endorsed mail registration -- an issue resisted by legislators who say they fear increased voting fraud -- but later retreated from that position. He also abandoned support for an idea to allow motor vehicle employes to register voters and ultimately established the commission to study the whole issue.

Supporters of mail registration contend there have been few, if any, cases of significant mail fraud in voting in the United States. They charge opponents unfairly want to restrict the numbers of citizens who may vote.

"We hold no illusions about the probability of passage . . . ," the groups said in a statement, "but in time . . . the level of acceptability and support will increase."