Gov. Harry R. Hughes and Sen. Paul S. Sarbanes, leaders of Maryland's dominant Democratic Party, went into the final 48 hours before Tuesday's election maintaining large leads over underfinanced and still not well-known Republican challengers.

According to all polls and indicators, GOP gubernatorial nominee Robert A. Pascal and Senate candidate Lawrence J. Hogan are highly unlikely to break the hold of the incumbents.

Since the day he announced his opposition to Hughes in February, Pascal, the two-term executive of Anne Arundel County, has insisted that name recognition would not be a problem when Nov. 2 arrived because, "When I get on the tube, people will know me."

But lack of funds has prevented Pascal from "getting on the tube" in the Washington area since July and it is here, according to polls, that he is largely unknown. It is also here that Hughes is expected to run up his largest pluralities. Pascal has been on television the last two weeks in Baltimore and has campaigned hard there, but in a city with a 7-to-1 Democrat registration margin and high unemployment, Pascal is not considered likely to run strong there either.

Hogan, the 54-year-old Prince George's County executive, is better known among Maryland voters than Pascal, and has been able to raise more money, although not as much as he hoped, in his bid to unseat freshman Sen. Sarbanes. Nonetheless, Hogan's problems run deep: He has had less-than-enthusiastic backing from his own party, which has a history of infighting in Maryland. This lukewarm attitude toward his candidacy hampered his earliest efforts to raise money, and by Tuesday Hogan will have raised only about 60 percent of the $1 million he had counted on to wage a full-scale media campaign.

New polls released today by the Baltimore Sun and the Baltimre News-American-WBAL-TV, show the Democrats maintaining big leads over Pascal and Hogan. Sarbanes gained two percentage points on Hogan during the last month, according to the News-American-WBAL poll, to lead by 58 percent to 35 percent. Hughes retained a commanding 63-30 percent advantgage over Pascal.

The Sun poll showed Sarbanes leading Hogan 57 percent to 25 percent and Hughes whomping Pascal 61 to 21. In the Sun poll of Sept. 28, Sarbanes led 59-25 and Hughes led 60-25.

One of the question marks in the Senate race has been the presence in the campaign of the National Conservative Political Action Committee (NCPAC), which has spent about $650,000, most of which went for a media barrage denouncing Sarbanes. Although Hogan said several months ago that he hoped NCPAC would stay out of Maryland, he failed to denounce the group when it resumed anti-Sarbanes and pro-Hogan ads in August.

Sarbanes took the offensive against NCPAC, chastizing the group in public appearances for using "extremist tactics to manipulate and distort the political process." Sarbanes' repeated attacks on NCPAC led Hogan to state publicly a few weeks ago that he objected to the group's presence in the state and the attention being devoted to it in the press. But the denunciation apparently came too late.

Hogan, unable to bury the issue, complained that Sarbanes is using NCPAC to divert voters from the real issues and that the group's presence actually helped Sarbanes while hurting him. Hogan, a former three-term congressman, has been frustrated trying to get the press to focus on what he considers "the meaty issues," such as a 13-point crime program that contains some of Reagan's proposals for curbing narcotics trafficking.

Sarbanes, in response to these complaints, charged that Hogan could have prevented NCPAC from becoming a campaign issue by forcing the group to leave, as Republicans have done in other states.

Neither Hughes nor Pascal have had to deal with negative commercials. Pascal taped two negative commercials last month but scrapped plans to use them at the urging of advisers who told him they would only be effective if the race were close. With polls showing him trailing 2 to 1, Pascal decided to go with ads that emphasize his record and do not attack Hughes.

Pascal, in spite of lending his campaign $100,000, entered the last week with only $65,000 to spend on media. Rather than buy limited television exposures in the Washington area -- commercial time here is almost twice as expensive as it is in Baltimore -- he decided to advertise in the more limited and less expensive radio market.

Pascal held a fund-raiser in Montgomery County Monday, hoping to raise $40,000. About 200 tickets were sold at $100 a ticket but the profit was only $10,000 because $10,000 was spent on food and trappings.

"That's been the problem the whole campaign," said a high-ranking member of the state GOP. "Why spend $10,000 when $2,000 would do. You can't waste money and be opulent when you haven't got money."

By contrast, the Hughes campaign hoarded its resources until after Pascal went on television in Baltimore, and has been blitzing all areas of the state during the last few days.

Of the three new Hughes ads, the one that Hughes and his aides are most proud of was filmed at a picnic and shows Hughes, dressed casually and mingling with people, choosing up sides for a softball game. While the film runs, Hughes talks about helping people as governor.

"It's good stuff," said a Pascal campaign aide. "It makes Harry look like a human being."

Despite their apparent leads, Hughes and Sarbanes have conducted vigorous campaigns. On consecutive mornings last week, Hughes was at his first campaign stop at 6:45 a.m. and 5:45 a.m. respectively. His days have been long and many of them have been spent campaigning in a group with Sarbanes, Attorney General Stephen H. Sachs and Comptroller Louis L. Goldstein.

The Pascal campaign has been hamstrung throughout October because the candidate has had to devote much of his time to fund-raising. Even without that, Pascal has not kept up as exhaustive a schedule as Hughes.

During the final weeks, with polls showing him not even doing well against Hughes among Republicans and voters who consider themselves conservative, the moderate Pascal has tried to move to the right. He changed his stance on Medicaid funding for abortions, saying 10 days ago that he would take out the clause in the current law that allows for Medicaid funding if the mental health of the mother is endangered.

Pascal also has tried to emphasize the fact that he favors capital punishment while Hughes opposes it and recently sent out a letter to more than 1,000 voters emphasizing his belief in voluntary prayer in the schools and his support for a package of bills on school prayer that will come before the legislature next year.

If there has been a major difference between the two campaigns, it has been Sarbanes' willingness to debate Hogan anytime, anyplace, on both radio and television. The Hughes people would agree to only one televised debate, although the two candidates did appear together in four other occasions.

Hogan campaigned yesterday in the Baltimore area, courting voters from ethnic and blue-collar groups who he is relying on. Sarbanes attended rallies in Prince George's and Montgomery counties and in Baltimore. Pascal went to functions in Baltimore and Anne Arundel counties, while Hughes spent the day in Western Maryland and Baltimore.