When Interior Secretary James G. Watt abruptly fired 28 departmental lawyers last spring, critics charged he was putting politics ahead of proper personnel practices. Now Watt is trying to fill some of those jobs -- and running into even an hotter crossfire.

The Merit Systems Protection Board and a House subcommittee are investigating charges that the Interior Department actively sought out Republicans for these career jobs, which are supposed to be filled through the normal civil service procedures.

In one case, a lawyer was offered a job after an assistant to Watt cited these qualifications: "In addition to being my brother, this gentleman is a good Republican and would be among the brightest and most dedicated, hard-working young attorneys you could possibly find."

Watt is under fire on Capitol Hill not only for the way he went about filling the jobs but also for the fact that he found the vacancies to fill. Just two weeks before his department announced six openings in the solicitor's office, Watt wrote Rep. Edward J. Markey (D-Mass.) that a serious budget crunch required severe personnel cutbacks at his department.

The budget problem was the Interior Department's original explanation for the event that sparked the hiring controversy: Watt's decision in March to order a reduction in force (RIF) that put 51 employes, most of them lawyers, out of work.

That action prompted angry complaints from some environmental groups and Democratic House members, including Markey. Now Markey says the way Watt has handled the lawyers' jobs is part of a general effort to politicize career positions in the agency.

Markey cites the case of Derb S. Carter, one of the lawyers who lost his job last March. Carter bounced back and applied for one of the six new openings the department announced in June.

In a interview for the job, associate solicitor J. Roy Spradley Jr. asked Carter what political party he belonged to and whether he ever had been involved in elective politics. Upon learning that Carter was from Oregon and lived in Virginia, Spradley said, "Well, I guess that's better than Massachusetts."

Carter was not hired and he filed a complaint with the merit board charging that the interview was an illegal interjection of politics into civil service hiring.

Richard R. Hite, deputy assistant secretary of interior, acknowledged yesterday that Spradley asked about Carter's political party and made the comment about Massachusetts.

"It was extremely poor judgment, but it wasn't illegal," Hite said. Hite said the agency did not violate the law that prohibits political affiliation from being considered in filling career jobs because Spradley, the interviewer, would not make the final decision on hiring.

To complicate matters, two women who worked part-time as attorney advisers for the solicitor's office in Minneapolis until they lost their jobs with the 49 others have charged the agency with sex discrimination.