By JAY DUCASSI

Guillermo Novo Sampol, the leader of an anti-Castro organization that U.S. authorities believe is linked to the terrorist group Omega 7, has issued a statement from his Connecticut jail cell suspending the "activities" of the organization until he is freed.

Novo's action formalizes the slow deterioration of the New Jersey-based Cuban Nationalist Movement (CNM), following the arrests of several of its leaders in the past four years.

Novo himself is serving the last leg of a 4 1/2-year sentence for perjury in connection with the assassination of former Chilean diplomat Orlando Letelier in 1976.

In a press release issued from Danbury Federal Correctional Institute Nov. 3 and received by The Herald during the weekend, Novo, national leader of the CNM, said the "suspension of activities" was motivated by the "circumstances and events surrounding the arrest" of Armando Santana in West New York, N.J., on Oct. 9.

Santana, self-proclaimed leader of the New Jersey branch of the CNM, was arrested on false passport charges by members of the Joint FBI-New York Police Task Force on Terrorism.

Task force investigators believe Santana is a top operative in the Omega 7 terrorist group. They say the CNM itself is connected with Omega 7, and has carried out assassinations and bombings for the terrorist organization in the past three years, a charge Novo has repeatedly denied.

Novo says one of the reasons he is suspending CNM activities is that the group is conducting its own investigation of Santana's possible involvement with drugs.

"We're very disturbed by any wrongdoing by any member of the CNM," Novo told the Herald in a telephone interview Monday.

Novo added that another reason the actions of the 22-year-old organization are being suspended is that the group "has fallen apart a little bit in the past four years," since the arrest of several of its leaders, including Novo's brother Ignacio and Alvin Ross Diaz, in connection with the Letelier murder investigation.

Novo said when he gets out of prison in November 1982, he will reorganize the CNM, and may move its headquarters from Union City, N.J., to Miami or to a foreign country.

One official close to the task force investigation said the real reason for Novo's action is to prevent a takeover of the organization by Santana, who is 10 years younger than Novo and seems to have the support of the younger CNM members.

"There's pretty much no question that that is what is going on," the official said.

Santana, free on bond, could not be reached for comment Monday.

Novo was recently in the news when he was mistakenly released from prison last month, with more than a year left on his sentence. He returned to jail on his own when authorities realized their mistake.