The Reagan administration today will propose to give bank holding companies specific authorization to engage in insurance underwriting and real estate development and brokerage as well as other financial services.

Treasury Secretary Donald T. Regan will propose the change from current law in the form of an amendment to the Bank Holding Company Deregulation Act of 1982 during testimony before a Senate banking subcommittee.

In an interview late yesterday, Regan said the amendment was drafted because of concern by the banking industry that the Federal Reserve would have too much latitude in deciding which services it could offer.

Today's hearing was to be devoted to a bill that would begin to remove the legislative barriers between commercial and investment bankers erected by the Glass Steagall Act almost a half century ago. It would allow commercial banks to underwrite revenue bonds and sell mutual funds. Some brokerages, on the other hand, could own banks if the legislation passed. All services would be conducted through bank affiliates and would be subject to the same regulation and tax basis as comparable services offered by brokers.

Regan said yesterday he thought the administration's bill enjoyed the support of the securities industry and the majority of banks. Some banks would prefer to offer the financial services directly without being obliged to establish holding companies. Moreover, some smaller brokerages fear a takeover by major banks.

As for a full-scale review of Glass Steagall, Regan said he thought it would come later in the year along with a review of the McFadden Act, which prohibits banks from making acquisitions across state lines.