Senate investigators were reported yesterday to be checking into an "unusual pattern" of national bank charters granted during the Nixon administration to Texas friends and associates of John B. Connally.

In a copyrighted article, the Dallas Morning News said the inquiry was centered on seven Texas bank charters approved by the U.S. Comptroller of the Currency between 1970 and 1973 against the advice of his deputy comptroller and most of his staff.

Four of the charters were awarded in 1971 and 1972 while Connally was secretary of the treasury, which includes the comptroller's office. Two others were granted shortly before Connally's nomination to the cabinet post in December 1970 and another was approved several months after Connally left Treasury in mid-1972 to campaign for Nixon's reelection.

The former Texas governor had no immediate comment, but the communications director for his Republican presidential campaign, Julian Read, denounced the inquiry as "a political witchhunt."

A spokesman for the Senate Banking Committee said the granting of the charters came under scrutiny in the course of a larger study of bank chartering procedures from 1970 to 1978. The overall investigation is expected to produce a majority staff report later this year and perhaps public hearings.

"We're putting the study together in bits and pieces," the spokesman said. "We have not reached any conclusions."

Read protested that "there's no way Gov. Connally has ever used any political influence to help any of his friends. We think it's the best evidence so far that Gov. Connally's campaign is succeeding better than any of his enemies ever thought."

There is no indication as yet that Connally personally intervened in any of the seven cases. The charters were granted by Comptroller William B. Camp, who was appointed by President Johnson in 1966 and reappointed by Nixon.

For both appointments, Camp, a native Texan who died in 1975, had the support of former LBJ aide Jake Jacobsen, who was close to Johnson and Connally. Jacobsen later gained notoriety as the man who was convicted of giving the milk price supports bribe during the Nixon administration that Connally was found innocent of accepting.

According to the Dallas Morning News, the seven bank charter awards under scrutiny are: Love Field National Bank in Dallas, 1972; Chevy Chase National Bank in Austin, 1971; Guaranty National Bank in Houston, 1970; Metropolitan National Bank in Houston, 1972; Peoples National Bank in Spring Branch, 1970; First National Bank in Round Rock, 1972, and Meadowbrook National Bank in Fort Worth, 1973.

The Love Field charter went to Mike Meyers, who had served as an aide to Connally when he was governor and who was also associated with him in a real estate venture in Fort Worth. The Round Rock bank charter went to Tom W. Miller, son of the former conservative Democratic mayor of Austin.

Allegations of croynism involving Connally in the awarding of bank charters are not new. When he was governor, he and his appointee to the state banking board, Robert S. Strauss, now one of President Carter's top advisers, were accused in news articles of granting charters to Democratic friends.

At a banking board charter hearing in 1969, Strauss conceded that some of his friends and associates had received state bank charters while he was on the board, but he said that to see "anything sinister in the relationship . . . would be the worst form of McCarthyism."