The House Judiciary Committee yesterday knocked out a controversial section of a lobby disclosure bill that would have required registered lobbyists to disclose major efforts to generate grass-roots letter-writing campaigns.

By a 26-to 8 vote, the committee decided that lobbyists would not have to reveal what mailings they made in an effort to get people to pressure Congress on an issue or what ads they bought in various media urging people to write their congressmen.

Rep. Don Edwards (D-Calif.), who offered the amendment knocking out the section, said he believed it was "unconstitutional."

Edwards said he believed requiring disclosure would abridge the right of people to petition the government, as guaranteed by the First Amendment.

His position was supported by the American Civil Liberties Union, evironmental groups and business groups which oppose the bill or want it significantly modified.

But Rep. Tom Railsback (R-Ill.) said grass-roots lobbying campaigns are "right now the most effective kind of lobbying" and only organizations who lobby enough to be included in the bill would have to disclose.

"This just prevents commercialized grass-roots lobbying", Rep. George Danielson (D-Calif.) said, adding it was the "public's right to know" who instigates floods of mail on an issue.

Common Cause Vice President Fred Wertheimer said the issue would "become a key floor fight" when the bill goes to the House. He called generating grass-roots pressure" the growth area and major activity of lobbying today." Common Cause is the major backer of the lobby disclosure bill.

Grass-roots letter-writing campaigns have weighed heavily in recent House votes defeating a bill to create a consumer protection agency, defeating a bill to expand picketing at construction sites and winning strong anti-abortion language on a Medicaid funding proposal.

With the controversial issue out of the way, it is expected the Judiciary Committee will report out a lobby disclosure bill today. The bill seeks to tighten loopholes in a 1946 lobby disclosure act, which requires only those whose "principal purpose" is lobbying to register and report lobbying expenditures.

The bill under consideration by the Committee would require any organization spending more than $25,000 a quarter on lobbying or any organization which employs one or more people who lobby on all or part of 13 days in a quarter and spend more than $2,500 in a quarter to register as a lobbyist. They would have to report their activities, their positions on bills and their expenditures over a certain amount.

A tougher lobbying disclosure bill died in the waning days of the 1976 session. Danielson predicted that the current, modified bill would pass the house.

A stronger bill, requiring lobbying organizations to reveal contributors and report lobbying to procure government contracts is pending before the Senate Governmental Affairs Committee.