One of three leaders of Rhodesia's biracial transition government charged today that last week's five-day election to establish a black majority government was "grossly irregular."

The Rev. Ndabaningi Sithole, whose party was trailing in early election results, said he would not recognize the elections until a committee investigates the alleged voting irregularities.

Sithole's charges came as high election officials defended a government claim that 63.9 percent of those eligible cast ballots in the election, which ended Saturday.

Initial unofficial results showed Sithole's party trialing far behind Bishop Abel Muzorewa's United African National Congress.

First results were expected tonights or Tuesday, with the final count expected on Wednesday.

Meanwhile, election returns from Rhodesia's biggest province showed a voter turnout exceeding the number of registered voters, but government officials insisted that the discrepancy did not indicate fraud.

Malcolm Thompson, chairman of the election directorate, said the 101 percent turnout recorded in the three districts of Mashonaland Province indicates that voters cast their ballots in areas where they were not residents. Eligible voters were permitted to vote anywhere in the country.

Prime Minister Ian Smith predicted that the high turnout in the election would cause the United States to Lift Economic sanctions against Rhodesia.

"It would be the height of immorality, evil even, to go on supporting a gang of Marxist terrorists," Smith said referring to the guerrillas who opposed the election.

In Lusaka, Zambian President Kenneth Kaunda condemned the Rhodesian election, saying, "How can they say voting was fair and just when there was no voters roll and elections were held under martial law?"