James Vorenberg '49, professor of Law and master of Dunster House, Friday accepted the post of special counsel to the Massachusetts Senate Ethics Committee, effective immediately.

The Massachusetts State Senate established the Ethics Committee two weeks ago after the convictions of State Sen. Joseph J. C. DiCarlo and State Sen. Ronald C. MacKenzie for extortion.

Vorenberg, who will remain master of Dunster House, said yesterday the time he will spend advising the committee will not detract from his time teaching. "This is by no means a full-time position; it has a very limited time commitment," he said.

Advice, Free of Charge

Vorenberg said he accepted the appointment as legal advisor to the Ethics Committee on the condition he would not be paid for his services.

State Sen. Chester G. Atkins, chairman of the Ethics Committee, said yesterday Vorenberg's decision to work without compensation was unusual. "Not many people decide to work on a legislative committee without pay," he added.

Atkins said yesterday the Ethics Committee will investigate conduct of legislators, take reports of violations of Senate rules and report back to the full house if violations have occurred.

Financial Disclosures?

The committee can also require Massachusetts state representatives to make financial disclosures.

It has not been determined whether these financial statements will be made public.

The Ethics Committee holds public hearings, and will report back to the full body with a draft of a new code of ethics.

Two-Week Search

Atkins said the Ethics Committee began searching two weeks ago for a legal advisor to the committee.

"We were looking for someone with prestige in the law profession and the political and academic communities," he said. "Vorenberg was recommended in all of these areas."

Vorenberg will be the only special counsel to the committee.

The Law professor was one of six men under consideration by Gov. Michael S. Dukakis in January for the post of chief justice of the Massachusetts Superior Court.

Vorenberg previously served as executive director of a federal crime commission under President Johnson and was a special consultant to the Watergate Commission.

A federal jury convicted DiCarlo and MacKenzie of extorting $40,000 from a New York construction management firm.

DiCarlo and MacKenzie were accused of demanding money from the company to produce a "whitewash" report.

The lawyers of DiCarlo and MacKenzie have said they will appeal the case. DiCarlo and MacKenzie are to be sentenced on Wednesday.