The executive council of the AFL-CIO voted today to wage a computer and communications struggle with conservatives for political clout.

The federation's battle station will be a $3 million, Washington-based "labor institute of public affairs," which will get its first test this year in congressional election campaigns.

"With a small professional staff, the institute will create and direct a program of direct communications with the union constituency and the general public to increase and improve their appreciation of labor's point of view on the crucial economic, political and social issues of the day," the council said in the report released here today at its annual midwinter meeting.

The institute will use the latest computer, polling, direct mail and television production technology, employed with great success by conservative groups, to try to get its message across to every union member in the nation, the council said.

The technology will give labor the ability to target members down to the precinct level, cross-reference households and send personalized letters instead of the "Dear Brother" messages it now mails.

The development is welcomed by federation leaders such as Kenneth E. Blaylock, president of the American Federation of Government Employes, who have long complained that the AFL-CIO badly trails conservatives in using the media.

"It's been a very real problem," one that has contributed to the view that union leaders are out of touch with their members, Blaylock said in a Washington interview before coming here this week.

"Labor was late getting into the media. It's not so much that we have moved away from our people on the issues. It's just that we haven't kept up with the times in terms of communicating with them," Blaylock said.

Chief AFL-CIO spokesman Murray Seeger said today that the institute should be fully operational in time to aid the federation's push this year to elect a pro-labor Congress. For example, Seeger said the institute could be instrumental in countering conservative attacks on pro-labor incumbents such as Sen. Paul S. Sarbanes (D-Md.).