More than 250 green-and-white signs soon will be posted at street corners near the Convention Center, the Capitol and Union Station to help tourists and other Metro riders find nearby subway stations, transit officials announced yesterday.

The first signs, affixed to traffic signal poles at 10th and H Streets NW, were unveiled at a brief mid-day ceremony. Officials said that a total of 57 signs would be installed in the Convention Center area in the next two weeks.

"For a long time we have wanted to make it easier for people to find Metro stations, particularly visitors to our city," said Carmen E. Turner, Metro's general manager.

The transit authority long has been criticized by local government officials and passengers for failing to provide adequate signs and other information near subway stations and bus stops. The new signs, financed by an $18,516 grant from the federal Urban Mass Transportation Administration, are part of an effort by transit officials to respond to these complaints.

The first signs, nevertheless, appeared to have raised prospects of further confusion, at least temporarily. The two signs at 10th and H Streets NW said: "METRO CENTER STATION 2 BLOCKS." A green arrow pointed south.

There is, however, no subway entrance two blocks south of the intersection where the signs were posted. Instead, a would-be patron in search of the Metro Center station would have to walk one block south, turn right and go one block west, to 11th and G Streets NW.

Metro officials said they would soon act to rectify the apparent mishap by putting up additional signs at 10th and G Streets NW, which will point toward the Metro Center entrance. "Someday there will be a sign there. There may not be one today," a Metro spokesman said.

In the Convention Center area, the new signs will point either to Metro Center or to the Gallery Place station, whichever is closer. During the next few months, Metro and District of Columbia officials plan to install about 135 signs pointing to subway entrances at Union Station and another 75 signs pointing to the Capitol South stop, at First and D Streets SE.

Recently, Metro officials began correcting erroneous signs and improving public announcements at National Airport and other stations served by the Yellow Line. The transit agency also is evaluating plans to post more information at bus stops, a proposal that drew support last week from the Northern Virginia Transportation Commission.