Prime Minister George Chambers' opposition to the invasion of Grenada has touched off a political storm at home and within the Caribbean community.

Labeled "a black sheep" by local newspapers for his failure as chairman of the major organization of Caribbean nations to keep the islands politically united, Chambers is also involved in an increasingly bitter argument with Tom Adams, the prime minister of Barbados, over whether Adams told him the invasion was coming.

On Friday, Adams asked Chambers to recall his ambassador to Barbados after publicly stating that the ambassador was "an outright liar" for denying that he was informed of plans for the invasion.

In another development, a Cuban boat registered as the merchant vessel "Vietnam Heroico" is anchored here under heavy naval guard and is not expected to leave until Tuesday. The ship arrived Friday evening from Grenada with an undisclosed number of people aboard and was granted permission by the Ministry of National Security to dock here to obtain water and goods. A maximum stay of five days was granted the ship, which sources said could conceivably return to Grenada to take captured Cuban soldiers home.

Chambers' government responded to Adams' blast today in a speech by Trinidad's Minister for External Affairs, Basil Ince, in which Ince defended the ambassador's story and said Chambers has not been "lying" to the nation when he said he did not know about the invasion until after it began.

The differences in recollection are important because of what officials in Jamaica, Barbados and Trinidad describe as long-standing U.S. pressure on Caribbean nations to intervene militarily in Grenada.

These officials assert that this pressure intensified after the assassination of Grenadan prime minister Maurice Bishop on Oct. 19. The officials would not provide details of the pressure, which the United States has strongly denied.

Chambers and Forbes Burnham, prime minister of Guyana, led the opposition to invading the island. Chambers said he disapproved of an invasion during meetings here with Caribbean leaders on the weekend before the Tuesday morning invasion, noting that he needed approval of his parliament before he could send troops to Grenada.

At that point, the other Caribbean leaders apparently excluded Chambers, chairman of the Caribbean Community (CARICOM), from further discussions or, Trinidadian officials suspect, were urged to do so by the United States.

Chambers was not invited to a three-hour meeting held yesterday in Barbados by Jamaican Prime Minister Edward Seaga, Adams of Barbados and Eugenia Charles, prime minister of Dominica and head of the Organization of Eastern Caribbean States.

Chambers also has come under fire at home. He is being portrayed here as out of touch with the other Caribbean nations and "failing in an hour of crisis," according to an editorial in the Guardian.

A poll published today in the Sunday Express newspaper showed 61 percent of Trinidadians supporting the invasion and U.S. involvement. In addition, 56 percent said they supported committing Trinidadian troops to the assault on Grenada, which is less than an hour's flight away.

Only three other Caribbean nations--Belize, the Bahamas and Guyana--sided with Trinidad in opposing the invasion and all four were excluded from final planning for the invasion, even though much of the planning was done here in Trinidad while meetings chaired by Chambers were going on.

In his only statement on what happened at the meeting of Caribbean leaders on the Saturday night and Sunday morning before the invasion, Chambers said he thought the group had agreed on applying sanctions against Grenada, sending a fact-finding team to the island and not using military force against its revolutionary government.

Chambers' claim has sparked angry recriminations. At home he is facing criticism from his political rivals who say his "lack of leadership" has embarrassed the nation while his ambassador is being branded a liar.

"It was a definite slap in the face for the people of Trinidad and Tobago not to be told of the invasion ," said Karl Hudson-Phillips, head of the Organization for National Reconstruction, the second largest political party. "One is only left to speculate why the Caribbean heads of government thought it necessary not to advise the prime minister of Trinidad and Tobago . . . . "

Chambers has said that he learned of the invasion Tuesday morning from the U.S. Embassy here.

Adams said that he told Trinidad's ambassador to Barbados the day before the weekend meeting that he could not attend the Port of Spain conference because plans had already been made to go ahead with "military intervention."

Chambers' ambassador to Barbados, Basil Pitt, has denied that he was told of the plans.