The White House, which has been tightening reporters' access to President Reagan as the campaign moves into full swing, yesterday barred coverage of remarks Reagan made to a group of corporate executives at the Old Executive Office Building.

Such remarks by the president to various groups invited to the White House are often open to news media coverage, but spokesman Larry Speakes yesterday announced that this session would not be.

He did not give a reason, but noted that reporters were allowed to witness Reagan's departure yesterday for Camp David for the weekend. Reagan paused briefly to answer questions shouted by reporters over the sound of helicopter engines.

In response to a protest from United Press International and the Associated Press, Speakes has agreed to allow the wire services to remain in the "pool" of reporters, photographers, and television personnel who follow Reagan when he greets supporters along fence lines while campaigning.

The White House had recently decided to exclude the wire services and limit the pool to a group of five, including two photographers, a network cameraman and soundman, and one television correspondent who would rotate with a newspaper writer. Others in the pool would have to watch from a distance.

White House officials say it was done for security reasons; some reporters said it was a move to cut down questions shouted at the president.

Speakes yesterday responded to questions about reporters' access to Reagan by noting that the president has held five formal news conferences this year, the same number as President Carter held in 1980. Carter held a sixth before the election and then held a series of "town meetings" around the country.

Reagan has held 26 formal news conferences since his inauguration, compared with 58 at the same point for Carter.