Several changes in Metrobus routes along Connecticut and Georgia avenues will go into effect Jan. 31, and may be followed by fare increases.

The changes were approved by the Metro board last November. Some changes the board originally had proposed were dropped because of opposition from Maryland and District residents.

Fare increases on three of the routes --L-3, L-5 and L-9 buses--are to be considered shortly by the regional Metro board. A 50-cent surcharge on the L-3 and L-9 buses has been proposed, as well as an increase in the L-5 bus fare from 65 cents to $1.10, or as much as $1.35. The increases would make the fares comparable to the cost of riding a bus to the new Van Ness subway station and taking the subway downtown.

The originally proposed Connecticut Avenue corridor changes were designed to save money for Metro and the local jurisdictions that support it by stopping virtually all bus runs at the Van Ness Metro station, forcing bus riders into the subway system.

The route changes were modified, however, after strong opposition at public hearings from elderly residents who live along Connecticut Avenue and from commuters who would be forced to take as many as two buses and a subway where they now ride a single bus.

Further changes in Montgomery-to-District bus routes are expected when the subway is extended to Shady Grove in late 1983.

The following are changes as of Jan. 31:

* The L-4 and L-8 buses, between Wheaton or Aspen Hill and the Federal Triangle, will stop at Dupont Circle after Jan. 31 (the original proposal called for the buses to stop at Van Ness). The L-4 buses to and from Wheaton will be renumbered L-6.

* L-3 and L-9 express buses between Wheaton or Aspen Hill and the Federal Triangle will have new stop restrictions. Boarding and deboarding will be allowed at all Maryland stops, but in the District only at McKinley Street, Van Ness, Florida Avenue and all stops between M Street and the Federal Triangle.

* The L-5 route remains the same but a fare surcharge may be imposed.

* The 5:05 p.m. T-6 trip from Dupont Circle to Pooks Hill will end at Montgomery College.

* The T-9 Westbard shuttle will be eliminated.

* The Y-5, Y-6, Y-7 and Y-8 trips along Georgia Avenue will have revised morning rush hour departure times. Timetables are available from bus drivers.

* The Y-9 Georgia Avenue express, which now ends at Leisure World, will be extended to the new but still incomplete Norbeck fringe parking lot on Rte. 28 just east of Georgia Avenue, and no longer will serve Leisure World. The Y-8 bus route will continue to serve the retirement community.

* The Z-4 Randolph Road line ending at White Oak will be extended to Old Columbia Pike and Randolph Road.

For further information about the route changes, call 637-2437.