Newton I. Steers, the Potomac millionaire vying for a chance to recapture the Maryland Congressional seat he lost two years ago, has spent nearly $135,000 in the 8th District Republican primary -- far more than any other congressional candidate in the state.

Steers' considerable expenditures became an issue this week when two of his major opponents in the four-way race -- state delegates Robin Ficker and Constance Morella -- accused him of trying to "buy" the election.

The attacks on Steers' spending were the first signs of rancor in what otherwise has been a polite contest between Steers, Ficker, Morella and Phillip Buford, a Bethesda engineer.

The man they hope to replace -- Rep. Michael Barnes (D-Md.) -- is running unopposed in the Democratic primary Tuesday.

Steers' campaign chairman, Howard Denis, dismissed the criticism.

"To the charge I simply say 'So what'," he said. "It's an insult to the Republican party and Montgomery County to suggest votes can be purchased. If money alone could win elections Nelson Rockfeller would have been president."

Campaign spending in the 8th District, which encompasses most of the affluent and prodominantly democratic voters of Montgomery County, far outstrips other congressional districts. Republican and Democratic candidates here have laid out upwards of $250,000 for the primary compared to combined expenditures of $438,000 for the state's seven other districts.

Morella herself expects to spend more than $70,000, of which $30,000 already has been disbursed for radio and television ads.

Ficker, who announced that he would not accept contributions from outside Montgomery County when he began his campaign, has spent around $17,000, according to statements filed with the federal Election Commission.

Buford has spent less than $5,000.

Steers, a businessman and lawyer who earned his fortune by starting a successful mutual fund in the 1950s, has poured $80,000 in personal loans into his campaign. Much of the rest of his campaign cache comes from individual contributions ranging from $100 to $200 and from the proceeds of a fund-raiser last December.

The former congressman has spent nearly $27,000 on a Capitol Hill political consulting firm, which has laid out campaign strategy and produced three television commercials and a special 12-minute film that Steers presents at campaign coffees.

Another $5,000 has gone to buy time for his 30-second TV commercials, now appearing on three Washington stations. Steers also has been paying a professional campaign staff, including a campaign manager and press secretary, since last fall.

"Newt is just determined to win," campaign manager Jeanne Miller said, adding that the campaign strategy was mapped out last fall with the knowledge that the effort might cost more than $100,000.

Miller had noted earlier in the campaign that the first obstacle the former congressman had to overcome "was, well, that he had lost once." Steers, who was elected in 1976, lost the seat to Barnes, then an unknown Democrat, in 1978.

Ficker first interjected the campaign financing issue into the campaign last month by touting the fact that he had "limited" his own contributions to a $100 ceiling.

The delegate then went on to attack Steers for raising $20,000 at a fund-raiser in Potomac last December where Sen. John Warner (R-Va.) and Warner's wife, Elizabeth Taylor, were the major draws.

"I find it appalling that Steers is pouring all that money in," Morella said. "It seems like he's trying to buy the election."

Staunch Steers backer, Del. Luiz Simmons brushed off the charges as an eleventh-hour effort to attack the acknowledged front-runner.

"It's the pot calling the kettle black," he said. "Where do you draw the line on what's excessive? The issue is not the amount, but where it comes from." CAPTION: Picture, Newton I. Steers . . . uses $80,000 of his own funds