It's been 10 months since President Carter sent the Senate two nominations to the Federal Election Commissions, and after the salvos that one of them ran into yesterday before the Senate Rules Committee, it was clear the fight is nowhere near ending.

It was also clear that White House handling of the matter was as much as target as the nominee, john W. McGarry, whom Carter designated to fill a Democratic slot on the six-member FEC.

The commission jobs, three of which go to each party, are because the FEC is the agency that polices presidential and congressional campaign finances and doles out public funds to presidential candidates.

McGarry has ecountered flak because he is a close friend of House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), and the other nominee, Samuel D. Zagoria, slated to fill a Republican vacancy, is seen by some GOP senators as a closet Democrat.

Yesterday, Zagoria, director of labor-management relations for the U.S. Conference of Mayors, was on vacation; so the focus was on McGarry, a special counsel to the House Administration Committee.

Sen. Mark Hatfield (R-Ore.) accused the White House of "lack of communication" with the committee and "inordinate delay" in responding to questions about McGary's business dealings.

"The White House has upon several occasions given this committee misleading statements on investigations it had promised or which were underway," Hatfied charged. "The adequacy of the investigation performed by the White House is still open to question."

Hatfield said that on Jan. 24 Sen. Howard W. Cannon (D-Nev.), then chairman of the committee, wrote a letter to the White House regarding an allegation "respecting the cash flow of a business in which Mr. McGarry had been a heavily invested partner" and asked that the FBI investigate.

Hatfield said the president's counsel, Robert J. Lipshutz, replied the next day that the matter would be probed and that the appropriate agency to investigate was the Internal Revenue Service, not the FBI.

"Months passed, and the committee did not hear one definitive word on the outcome of the promised investigation," Hatfield continued. On April 10 Lipshutz sent the committee's new chairman, Sen. Claiborne Pell (D-R.I.), "a weekly reasoned and speciously argued letter as to why no investigation had been or would be conducted," Hatfiled said.

Pell and Hatfield sent other letters in early May. All the committee got, Hatfield said "was a curious letter from Frank Moore (Carter's chief congressional liaison aide) to Sen. (Howard H.) Baker" Jr. (R-Tenn.)

In the letter Moore confused Zagoria's name with McGarry's and said the allegations had been investigated.

"Even giving Mr. Moore the benefit of the doubt, and saying that the misstatement of the names was an honest mixup, the substantive information he provided simply was not true," Hatfield charged, adding that the investigation had not been completed when Moore's letter was written May 5.

It was not until this month that McGarry submitted replies to committee questions and the White House sent a response accompanied by an FBI report, the senator said.

Neither Hatfield nor Martin Gold, minority staff director of the committee, would detail the allegation or the FBI response, although New York Times columnist William Safire has reported that "anonymous letters charged that a restaurant in Boston once partly owned by John McGarry had a cash register that was frequently 'skimmed.'"

McGarry was not asked about the charge yesterday, and Gold said he did not think the issue would be raised.

A presidential aide, however, said the White House delay in replying to the committee was caused by "the complexity of the questions asked."

"The FBI investigated the charges and while the results are confidential, we are very, very satisfied that, the allegations have been proved false," he said.

The aide said the IRS had been reluctant to investigate charges of skimming at the restaurant because of the propriety of interviewing the current owners and all the employes about charges "based solely on a anonymous letter."

Under questioning by Hatfield, McGarry admitted that he failed to list certain income or gave only vague information about its source on House financial disclosure statements for 1973 through 1976 required by his job.

"As a member of the Federal Election Commission, would you allow such generalizations," asked Hatfield.

"No, I think that's totally inadequate," McGarry said.

On his 1975 form, McGarry said he received $10,224 "owed from prior years not with the government" and $20,193 from the "sale of stock." He told the committee the first sum came from Melotone, a Summerville, Mass., vending machine firm for which he had done legal work, and that the second amount came from selling his interest in the Kenmore nightclub in Boston.

He also admitted not listing on the forms large sums he had received from a former law partner, Irving H. Sheff of Boston, who, he said, was paying him for his share of the partnership and for agreeing not to complete in seeking legal business.