Plans for Virginia's November legislative elections are likely to be thrown into chaos and the elections postponed, possibly until next year, unless there is a quick ruling on legal challenges to a General Assembly reapportionment plan, lawyers for the state argued today.

The attorneys warned that unless a panel of three federal judges rules on the plan by July 2 the planned Nov. 3 elections for all 100 seats in the House of Delegates could be delayed until after Christmas or until 1982.

But Appeals Court Judge John D. Butzner Jr., a member of the panel that will consider the challenges, said later that early action is not likely. "We won't deal with all of that until we hear the whole question on the 13th [of August]," he said.

The first indications that lawsuits over the House of Delegate's controversial redistricting plan may delay elections scheduled for all of its 100 seats came during a hearing today before District Judge D. Dortch Warriner, another judge in the panel.

State attorneys warned Warriner that timetables built into Virginia's election laws would delay the elections until at least Dec. 29 if a ruling were not to come until Aug. 13, the scheduled the date of the first full hearing on the central issues in the case. For each additional day after Aug. 13, they said, the elections would likely be postponed two or three days.

Such delays are likely to anger politicians from Northern Virginia and other fast-growing areas in the state, who had lobbied last spring to turn their population gains during the 1970s into legislative gains. But those gains have been thrown into question by the population deviations contained in the new plan that form the basis for most of the challenges before the court.

The judges must weigh eight separate challenges to the plan, most of which argue that it violates the Constitution's guarantee of equal voting representation because the population deviations between House districts are too wide.

The plan is also facing challenges by the American Civil Liberties Union and the NAACP under the federal Voting Rights Act on grounds that it dilutes black voting strength.

Today's hearing, whoever, bypassed those issues to focus on the procedural questions of how, when and whether to hold the scheduled House elections. In arguments lasting almost five hours, attorneys debated whether the court should cancel the elections, hold them under the old apportionment scheme, hold them under the new reapportionment plan, or draw an entirely new plan on their own before July 2.

Warriner said he would poll the other two members of the panel, Butzner and U.S. District Judge Glenn Williams, for an answer on the question.

Norborne Beville, a Northern Virginia attorney who is hoping to run for a newly created House seat in Prince William County, urged that the court hold the elections under the 1981 plan because a return to the old districts would leave Prince William with a third fewer delegates than it deserves.

But Warriner, who had also heard a plea for the old plan from a legislator who stands to lose his House seat under the new plan, was not impressed. "The truth of the matter is that it is equitable, or inequitable, or neither, depending on the area that you represent," he snapped back. "Isn't that right."

Earlier, Warriner rejected a suggestion by the state's attorney that he discontinue all action on the case until after the Justice Department completes its investigation into alleged Voting Rights Act violations -- a probe that is mandated by the law and is expected to take at least 60 more days.

"My instant response is that the appropriate thing to do, in light of the fact that the people of Virginia want to have an election and they want to have it in the fall, is that the court should proceed," Warriner said.

The judge also rejected a proposed compromise between the state and officials in Spotsylvania County that would have redrawn the county's legislative district to grant it greater legislative representation than the new plan had provided. Warriner said it would be "superfluous" for him to resolve such an issue before the central issues of the case are resolved.