A task force studying Maryland's banking industry today urged Gov. Harry Hughes to offer legislation giving banks from 13 southeastern states and the District of Columbia the authority to enter the state for a four-year period, after which all U.S. banks would be permitted into Maryland.

The task force, which Hughes appointed last summer to grapple with the politically sensitive issue of interstate banking, concluded in a 32-page report that a national system of banking was all but inevitable. But the task force recommended the creation of a reciprocal banking region for a four-year period that would allow Maryland institutions to expand within the region as well as let the regional banks enter Maryland.

Allowing interstate banking after four years would "demonstrate to the nation that the State of Maryland is inviting the spirit of maximum competition and expansion of commercial banking within its borders," the report said.

Maryland House Speaker Benjamin L. Cardin, a task force member, said four years of regional banking, followed by interstate banking, is "the right way to go. It's in the best interest of consumers and this state's banking industry."

Cardin said he expects the Hughes administration to file legislation along the lines of the task force recommendations in time for the 1985 General Assembly. Cardin, whose support is crucial to passage of the legislation, predicted the House and Senate would approve a bill allowing interstate banking.

The issue of interstate banking has in recent months split the powerful Maryland banking lobby. Supporters of interstate banking have said that out-of-state banks will bring new jobs, additional capital and more intense competition that will benefit consumers.

Opponents, including some who believe a form of interstate banking is inevitable, have voiced concern about which banks will be let into the state and what the competition will do to Maryland's smaller financial institutions.

Frank J. De Francis, Maryland's economic development secretary who was chairman of the task force, said four years of regional banking would "establish a playing field" for banks in neighboring states to establish outppsts in Maryland. The task force recommended that the banking region include Maryland, Virginia, the District of Columbia, Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky, Louisana, Mississippi, North Carolina, South Carolina, Tennessee and West Virginia.

Four years after the establishment of a regional banking system, large out-of-state banks such as Citicorp, the largest bank holding company in the nation, which wants to do business in Maryland, would be allowed to enter the state.