While much of America commemorated Martin Luther King Jr.'s birthday with parades and memorials, a group of black leaders met yesterday in Prince George's County -- which has one of the largest black populations of any suburban county in the nation -- to advocate economic and political strategies aimed at improving the status of blacks.

Invoking the name of the slain civil rights leader, speakers at the conference variously implored the audience to seek economic strength in coalition with whites and exercise unused political power to fulfil King's dream for America.

"The dream of Martin Luther King cannot wait any longer. We cannot be satisfied with just a birthday celebration," said the Rev. Terry Wingate, pastor of Purity Baptist Church in the District. He said blacks should do more than pray that problems like poverty and South African apartheid are solved.

"If the matter doesn't get taken care of by you, it's not going to get taken care of," he said.

It is economic power, said another speaker, that will gain influence for black Americans and improve their lives.

"When we talk about Martin Luther King in terms of today . . . take into account something economic," said Archie L. Buffkins, president of the Kennedy Center's National Committee on Cultural Diversity in the Performing Arts. Harnessing that economic power, he said, requires tapping blacks who already hold corporate positions.

"Don't demand that they get on the streets and demonstrate . Demand that they help change policy where they are," Buffkins said. "Many decisions affecting blacks are decisions made in the board room."

The conference, sponsored by the Southern Christian Leadership Conference of Prince George's County, drew an audience of about 100, many of them county residents. Prince George's, where 37.3 percent of the residents are black, is also home to a relatively affluent black population. According to the 1980 census, the median income for the 79,747 black households in the county was $20,900.

Unlike other speakers who called for independence among blacks, specifically political independence, Buffkins urged blacks to form coalitions with whites, as long as the coalitions are "based on mutual respect" and blacks share power equally.

"How in hell do you go the individual route when you don't have the money?" asked Buffkins. "You can't have economic power without a meaningful relationship with responsible white groups, based on mutual respect."

Buffkins said that before blacks can acquire economic power, they must be proud of their diverse culture and work to preserve this heritage. He criticized decisions by many of the most promising black students to attend white rather than black colleges.

"When we talk about Martin Luther King and his dream, he certainly was not talking about giving up what we have," Buffkins said. "Don't lose our beautiful schools. Don't lose the beauty of gospel music. Don't lose the air of handling that basketball."

As Buffkins urged blacks to pursue economic power, so did other speakers at the conference lobby for political activity: voting, running for office and participating in demonstrations such as the continuing protest against apartheid at the South African embassy.

At the conclusion of the speeches, several of the conference participants went to join in the day's demonstration in front of the embassy.

County Councilman Floyd E. Wilson Jr. said increased political power for blacks will require a turn-around in the apathy that has plagued Prince George's voters.

"The issue is whether to sit back and let someone else decide for us, or will we participate. That participation takes commitment," he said.