Representatives of several Washington groups last night accused Riggs National Bank of failing to live up to its obligations to invest in the local community -- charges the bank denies.

In a hearing before the Office of the Comptroller of the Currency, which regulates federal banks, speakers charged that Riggs' lending practices discriminate against black and low-income neighborhoods and charged that the bank lends large sums to South Africa and Chile.

Melvin Chrisman, Riggs' senior vice president, declined to say whether the bank makes loans to South Africa and Chile. "We don't discuss the identity of any particular borrower," he said.

The hearing was held in response to Riggs' applications for new branches at 1201 Pennsylvania Ave. SE. The D.C. Bank Campaign has protested the applications, charging failure by Riggs to comply with the Community Reinvestment Act. The Bank Campaign is a coalition which includes groups such as the D.C. Public Interest Research Group, Washington Inner-City Self Help and the Chile Legislative Center.

Bank Campaign representative Christine Root accused Riggs of discriminating against low- and moderate-income and minority borrowers and of callousness to the impact of displacement of low- and moderate-income families by the more affluent.

Approximately 100 people attended the hearing at the Washington Hilton, some of whom waved anti-riggs placards, cheered Bank Campaign speakers and hissed or laughed at Riggs' assertions.

"Nothing in the history of the development of Riggs' branches over the past 58 years suggests that Riggs failed to serve any segment of the community," said Riggs President Daniel J. Callahan III. Callahan said that Riggs serves a broader area than just D.C. and has a broad range of services and customers. "Fifty percent of our loans are made to local consumer customers who provide us with only 33 percent of our total deposits," he said.

Callahan noted Riggs' participation in projects including financing for renovation of the O Street Market in the Shaw urban renewal area, financing for construction of a new 150-unit project for low- and moderate-income residents in Southeast Washington, and financing for purchase and rehabilitation of the 2,200-unit Shirley-Duke project in Alexandria.

In cross examination, Bank Campaign member Edgar Lockwood suggested that only 20 percent of the units in Shirley-Duke would be rental subsidy units. Riggs representatives also conceded that Riggs was providing $8 million of the financing, with $70 million more coming from a government agency.

According to the Bank Campaign, while approximately the same number of houses were sold in each area, 143 mortgage loans were given by Riggs to purchasers in Ward 3, while only 4 mortgage loans were made by Riggs in Wards 7 and 8.