Attorney General William French Smith summoned reporters to the Justice Department yesterday to defend the administration's position on the Voting Rights Act and civil rights in general.

Asked about charges that recent administration decisions have been racist, Smith replied, "I say it's just totally untrue. It's categorically not so. The fact that the president is taking the position he's taking is based entirely on the merits. There has been no retreat on the overall question of discrimination."

Smith said the House-passed extension of the Voting Rights Act backed by civil rights groups and now co-sponsored by 62 members of the Senate is not what the Reagan administration wants, but he would not say whether President Reagan would veto such a bill if it comes to his desk.

Wednesday night in a CBS interview with Dan Rather, Reagan first said he would not veto the House-approved bill. "I don't know of anything that is in it that would make me veto it," he said.

But after a brief break in which he met with two White House officials, Reagan said that he had misspoken and that he was in fact willing to accept only a simple 10-year extension of the existing law with some modification to allow "bailout" for covered states after a period of good behavior.

The House bill goes beyond a simple extension of the act on one important issue: the test to be used in deciding whether state and local electoral laws are illegal. The House bill says it is enough to prove such laws have discriminatory effects. The administration is backing what civil rights groups say would be a crippling amendment that would make state and local election procedures illegal only if it could be proved that they were adopted with discriminatory purposes in mind.

The administration says an effect test would lead, as Smith put it again yesterday, "to quotas in the political process."

Proponents say the administration's quotas talk is a red herring, and that it would be impossible in many cases to meet the intent test; the law thus could rarely be enforced, they say.

Meanwhile, as hearings on the extension continued yesterday before a Senate Judiciary subcommittee, Rep. Henry J. Hyde (R-Ill.) said the House bill passed only because many members were afraid to cross civil rights groups threatening to brand them as racists. He said many members who favor voting rights objected to the measure but voted for it anyway.

"By the time it reached the floor, suggestions that alternate views should be considered were quickly met with harsh charges that any deviation whatsoever . . . merely reflected 'code words' for not extending the act," he said.

"This intimidating style of lobbying had the ironic effect . . . of limiting serious debate and creating a wave of apprehension among those who might have sincerely questioned some of the bill's language," Hyde said. "No one wishes to be the target of racist characterizations."