The possibility that Puerto Rico's offshore oil and natural gas was a factor in a Ford administration proposal for statehood for the island was raised yesterday. President Ford quickly denied it.

'That had no relevance at all," Ford told reporters in Vail, Colo. "That was not a matter that, at least, I considered. I had heard nothing of any consequence concerning it."

At the same time, President-elect Jimmy Carter took a more cautious approach to statehood than Ford, saying that any such proposal should come first from Puerto Rico.

The possibilty that Puerto Rice's offshore mineral rights are involved was raised yesterday by lawyers representing the island.

But White House aides insisted that the statehood proposal was made on New Year's Eve by an outgoing President because Puerto Rico is undergoing its own political transition. Puerto Rico's Gov.-elect Carlos Romero Barcel, who is to be sworn in today, campaigned on a platform of no opposition to statehood. Romero defeated Gov. Rafael Hernandez-Colon, who said he was opposed to statehood.

"The President wanted to make the announcement before the outgoing governor left office and before the inauguration of the new governor," James M. Cannon, executive director of the White House Domestic Council, said yesterday. "He felt the timing of his announcement would be the least politically motivated way to propose statehood."

In Vail, White House aides said that Ford proposed that Puerto Rico become the 51st state because he is determined to be President until he leaves office on Jan. 20. Aides said this is why he also is thinking of lifting controls on gasoline.

At the same time, lawyers representing Puerto Rico claimed that the statehood proposal might have something to do with a move to federalize Puerto Rico's offshore oil and gas deposits. The island does not produce any oil and gas, but at least two major oil companies have done exploratory drilling in the Atlantic north of Puerto Rico.

"I'm not suggesting that President Ford is tying statehood in with offshore mineral rights," said Richard Copaken, a lawyer with Covington & Burling, which has represented Puerto Rico in its attempts to become a member of the Law of the Sea Conference. "What I am suggesting is that Puerto Rico's offshore rights have been discussed at the White House, which may be the reason for the timing of the statehood proposal."

Puerto Rico believes that its commonwealth status gives it the rights to all its offshore oil and gas "out to the limits of exploitability," which is 15 or 16 miles north of its Atlantic shores.

Whatever oil and gas Puerto Rico has is believed to lie along the shelf that runs out under the ocean along the island's northern shore. At a distance of about 16 miles from the island, the shelf drops into a trench that is too deep to drill for any oil.

Last July, Hernandez-Colon wrote a letter to Secretary of State Henry A. Kissinger asking that Puerto Rico be granted observer status at the Law of the Sea Conference now being held in New York. Hernandez-Colon also asked Kissinger to let Puerto Rico sign the new Law of the Sea Treaty.

Hernandez-Colon pointed out in the letter that 24 other island governments were represented at the conference, including the Cook Islands, which are owned by New Zealand, the Dutch Antilles, owned by the Netherlands, and the Faroe Islands, possessions of Denmark.

"This leaves Puerto Rico as quite possibly the only island government in the world," Hernandez-Colon said, "that may not receive resource rights under the current draft language of the Law of the Sea Treaty."

Kissinger denied both requests, though it took him two months to do so.

"We believe that the question of Puerto Rico's rights to offshore resources should be addressed within the content of U.S.-Puerto Rican relations," Acting Secretary of State Charles W. Robinson wrote to Hernandez-Colon on Sept. 14, "rather than at a major international treaty-negotiating conference, such as the Law of the Sea Conference."

Puerto Rico was anxious to get to the Law of the Sea Conference because it fears it may lose the offshore oil rights it thinks it has. Covington & Burling's Copaken said that if Puerto Rico became a state it would give up most of the rights it has to offshore oil and gas.

"It's not clear what states' rights are on offshore mineral resources," Copaken said. "Congress in the Submerged Lands Act gave exploitation rights to the states for the first three miles and for Texas and Florida for about nine or 10 miles, but that's all."

The issue of Puerto Rican offshore oil rights may have surfaced again last month when Hernandez-Colon wrote Carter to raise the same questions he had raised with Kissinger.

"This may have something to do with the timing of President Ford's proposal," Copaken said. "He may have been reminded of it by his staff, who would have heard about the letter to Carter."

Copaken speculated that Ford might have timed his statehood proposal as a gesture to the incoming governor, Romero, but said that Romero had not spoken with anybody in the White House about Puerto Rican statehood. Copaken said Hernandez-Colon had not been contacted by the White House about it either.

Ford and his aides insisted publicly and privately that the statehood proposal was the President's and was not done in concert or in private dealings with the Puerto Rican statehood party. They admit only to having discussed it in June when Ford was in Puerto Rico for an economic summit meeting.

White House aides emphasized that the Republican platform supports Puerto Rican statehood, which makes it a good issue for Ford, who plans to play a major role in Republican politics when he leaves office.

In Americus, Ga., Carter said he thought Puerto Rico, not Washington, should make the first move toward statehood.

"During the campaign years," Carter said, "the position I took was that until the Puerto Rican people themselves expressed preference for statehood, Congress should not take the initiative, and I don't really know how the people feel. I think the last public opinion poll taken there showed that about 60 per cent prefer to stay as a commonwealth."