House Judiciary Committee Chairman Peter W. Rodino Jr., until a few weeks ago considered a shoo-in for a 20th term, faces an invigorated challenge by Newark Councilman Donald Payne in Tuesday's Democratic primary.

Rodino is still favored to win, but Payne's shoestring candidacy received a major boost with the May 13 defeat of Mayor Kenneth Gibson, Rodino's most powerful ally in the majority black and Hispanic district. Mayor-elect Sharpe James endorsed Payne, who is black.

Former presidential contender Jesse L. Jackson campaigned through Newark with Payne today, saying, "In the history of New Jersey, there has never been one black congressman. That's not fair." The district has been mostly black since 1972, but Rodino repeatedly has overwhelmed black challengers by focusing on his seniority -- he is third-ranking member of the House -- and his 38-year record in the House as a vigorous civil rights advocate.

Both Payne and Arthur S. Jones, who is also black and running in Tuesday's primary, have been beaten by Rodino in past elections. A fourth candidate, backed by political extremist Lyndon H. LaRouche Jr., is on the ballot but has not actively campaigned.

For the past three weeks, Rodino has saturated the radio waves with endorsements by Sen. Edward M. Kennedy (D-Mass.), Rep. Charles B. Rangel (D), Harlem's powerful congressman, and local black leaders.

In one radio ad, music from the movie "2001: A Space Odyssey" plays as Rodino points out that it would take until the year 2024 for a new congressman to achieve the seniority Rodino now enjoys.

Payne has bought less than $1,000 of air time. Overall, Payne said he has spent about $25,000, and has had no money for polling.

By contrast, Charles Scalera, Rodino's campaign manager, said Rodino has spent about $175,000, mostly for radio ads and direct mail. The city's unions are working for Rodino, mailing endorsements to members and running phone banks.

Scalera said polls by Peter Hart show Rodino's strength higher in May after Sharpe James' election than before. Two weeks ago, he said, 56 percent of voters disagreed with the statement that it is time for Rodino, 76, to retire.

However, Payne's campaign has geared up only in the last three weeks, since he won reelection to his South Ward councilmanic seat, in city elections that are separate from the statewide primary. A lack of organization was obvious today as he ran an hour behind in his campaign stops, and his rally with Jackson drew only a sparse crowd of about 60 people to the steps of the Essex County Hall of Records.

Nonetheless, Payne, 51, a former teacher and president of the National Council of YMCA's, said, "The momentum has shifted to our side. We're saying that now, it's our time. How long do we have to wait to have a black congressman?"

As Payne and Jackson took a handshaking tour through the shabby streets of downtown Newark, Payne workers handed out leaflets declaring that Rodino "has become New Jersey's richest millionaire congressman -- while the district has become the poorest city in the state."

At the Essex Plaza, a shiny housing project for the elderly, Payne's problems were obvious as Lula Robinson, asked about the race as she waited for Jackson and Payne to arrive, pulled out a crumpled envelope from her pocket. It was a letter from Rodino, thanking her for signing a petition about nutrition programs.

"When my husband passed, he Rodino sent me such a beautiful letter," said the 81-year-old retired factory worker.

Of a half-dozen senior citizens, all black, interviewed in a crowd of 50, all were for Rodino. "Experience means more than color," said Elizabeth Serious, 78.

On the steps of the Hall of Records, however, Kennedy Wilson, 44, a county worker, sported a Payne button. "Two years ago, I worked hard for Rodino," he said. "But we can no longer defer the wishes and hopes of the black people."

Essex County Executive Peter Shapiro, allied with Rodino, said, "Payne has a chance, but on any analysis of the issues, Rodino is as good a congressman as you can find among those sensitive to a minority constituency."