Democratic governors, seeking to assert their influence in the rebuilding of the party's image, today decided to expand the search for a new party chairman and encouraged other Democratic leaders to await the outcome.

The governors, saying they intend to play a more active role in shaping the party, plan to comb lists of former elected officials in hopes of finding a consensus candidate, while attempting to persuade party leaders in their home states to remain neutral for now.

The governors, frustrated by their inability to find a candidate for national chairman, hope to settle on someone within a few weeks, in recognition that to continue beyond that would be unfair to the six candidates now in the race.

The agreement came during a luncheon meeting in the hotel room of South Carolina Gov. Richard W. Riley here, where the National Governors' Association is conducting a seminar for newly elected governors.

Today's meeting capped a week of private lunches and dinners among the Democratic governors, other elected officials and party leaders seeking a replacement for Democratic National Chairman Charles T. Manatt, whose term expires in January.

"We want to get a large list to look at, and then refine that list," said Virginia Gov. Charles S. Robb, who organized today's meeting and has been a leader of the governors' effort.

"The governors are encouraging others in the process . . . to simply hold off on a final commitment" to one of the announced candidates, Robb added.

Also attending today's meeting were Govs. Michael S. Dukakis of Massachusetts, Scott M. Matheson of Utah, John Carlin of Kansas and George Nigh of Oklahoma, as well as incoming governors Madeleine Kunin of Vermont, Booth Gardner of Washington and George Sinner of North Dakota.

Several Washington-based political consultants were brought in to help shape a process for seeking a candidate and then rallying national committee members behind the choice.

The governors, acknowledging that they may not find the ideal candidate, say they believe that today's meeting marks a turnabout in their commitment to the party.

"I think it's time for Democratic governors to make a profound historical decision to get in and get involved," said Matheson, a former chairman of the governors' association.

Matheson, who leaves office in January, was the first choice of a number of governors for the Democratic National Committee post, but decided this week that he did not want to commit himself to the long hours and travel that the job entails.

This left the governors without a strong candidate, and helped precipitate a decision by Robb and others to convene today's meeting.

Those attending agreed to contact other Democratic governors and establish a search process for seeking a national party chairman.

One name that kept emerging is that of former North Carolina governor Terry Sanford, now president of Duke University. Privately, however, reservations were expressed about Sanford's age -- 67 -- and whether he would have the energy for the job.

The decision today reflected a feeling among elected officials that none of the six announced candidates satisfies all the requirements they are seeking.

The six people actively campaigning for the job are: Paul G. Kirk Jr., the party's national treasurer and a former aide to Sen. Edward M. Kennedy (D-Mass.); Robert Keefe, a veteran political consultant and former executive director of the national committee; Nancy Pelosi, a former California state chairman; Duane B. Garrett, former national co-chairman of Walter F. Mondale's presidential campaign; former Nebraska representative John Cavanaugh, and Sharon Pratt Dixon, a committee member from the District of Columbia.