The Comptroller of the Currency is opening a broad review of mortgage lending practices in the Washington area, sources said yesterday.

The nonpublic investigation will include interviews with executives of financial institutions, area real estate brokers and others involved in home mortgage lending.

The review is largely the result of a series of complaints by two citizens' groups here concerning bank lending practices and allegations of redlining policies against Riggs National Bank.

Although efforts by the groups -- the Metropolitan Washington Planning & Housing Association and the D.C. Bank Campaign -- to block the comptroller's approval of a new branch from Riggs failed, sources said the review was prompted by what the groups filed in the branch challenge.

Although one official emphasized that the comptroller's review is not directed at Riggs in particular, the source said that the bank and its major competitors for consumer loans here would all face scrutiny.

The review is designed to expand and improve the regular bank examination process carried out by the comptroller's office. It is designed to incorporate some of the standards of the Community Reinvestment Act and the Fair Housing Act in the examination process in order to take a broader look at banking practices when the annual examinations occur, a source said.

The Riggs branch application, which was filed with the comptroller last spring, is the bank's only pending branch move in the Washington area. But Riggs has also filled an application with the Federal Reserve Board to open an Edge Act office in Miami.

Riggs Chairman Vincent Burke said yesterday he had not been told of the comptroller's review, but also said he would be very interested in the conclusions of the comptroller's study.

Burke said Riggs hoped to open the branch at 48th Street and Massachusetts Avenue, NW between July and September.

Burke and other Riggs officials have vehemently denied the charges filed with the comptroller's office in connection with the branch application.

The charges indicated Riggs lending practices have denied access to loans to people in the city's poorer neighborhoods.

"Riggs' mortgage lending practices favor the wealthier, white neighborhoods at the expense of low-income and minority neighborhoods," the housing association and the D.C. Bank Campaign said in their filing with the comptroller's office.

Between 1972 and 1975, 72 percent of all Riggs single-family residential mortgage loans, or 79 percent of the bank's single-family mortgage money went to areas of the city west of Rock Creek Park, the groups said in their report.

The comptroller's review of mortgage lending practices here will focus on questions such as the geographic balance of mortgage lending in the city.

The review is unique both for its technique and its scope. It appears to be the first time the staff of the comptroller's office will extensively interview community members and others associated with the housing industry in an attempt to get a reading on lending practices.

But despite the magnitude of the review, the results are not expected to be made public when it is concluded by July 1. Instead, it will be used in conjunction with the regular bank examinations made by the agency's staff.

The report will be used as a backdrop for utilizing the Community Reinvestment Act to study banking practices in the Washington area.

The agency's review of the report submitted by the groups on Riggs directly led, however, to the board review in the area because officials of the comptroller's office felt there was a need for more comprehensive information of that kind in connection with their regular bank examinations.