A new report on the world's oil situation says that supplies will be adequate to meet demand "for the next several years and possibly into the early 1990s."

The report, submitted to the Trilateral Commission yesterday, disputes many earlier forecasts that oil demand will outstrip supplies by the mid-1980s.

But the authors of the report warn that adequate supplies in the near future are a mixed blessing because they will delay the intensive search for oil substitutes needed eventually. In addition, the report says, relatively cheap and plentiful oil discourages conservation.

The principal author of the report is John C. Sawhill, president of New York University, and former federal energy administrator. He was assisted by Keichi Oshima, professor of nuclear engineering at the University of Tokyo, and Hans W. Maull, European secretary of the Trilateral Commission.

They called for a strategy of raising what they called artificially low oil prices in Europe, Canada, Japan, and the United States and specifically recommended a higher federal excise tax on gasoline in the United States. In addition, they suggested a trilateral energy "summit" that would develop not only a higher pricing policy, but also pursue negotiations with the Soviet Union for technology and capital.

The Trilateral Commission, which has been meeting here since Sunday, is composed of 200 influential private-sector leaders from Europe, Japan, and North America who consult regularly and confidentially with government officials on international problems.

The commission, which had been scheduled to go out of business next July, voted yesterday to extend its life for another three years. A proposal to merge with the Atlantic Institute was scrapped.

The energy report says that additional flows from Alaska's North Slope, the North Sea and Mexico will keep oil supplies in rough balance with a growing demand of 2 to 3 percent a year for the next five to 10 years. Prices; barring a sharp cutback by Saudi Arabia or other major producers, would be stable or only slightly higher.

But sometime in the early 1990s, the report suggests, almost all OPEC producers will be cranking out oil at their peak, the non-OPEC production will begin to top out and "the world will have to look to the Saudis to provide any incremental supplies needed."

The authors urged the United States to maintain its "special relationship" with the Saudis for that reason.

One main theme of the report is that governments have not only failed to come to grips with the energy problem, but havenot shown they understand its magnitude or severity.

They divide the range of issues into short, medium, and longer-term periods. In the short term - for the next five years - the risk relates to a potential disruption of supplies through war or terrorism.

In the medium term - the following five years - there will also be the potential for financial crisis, initially among some of the poorer countries that might not be able to borrow enough money to pay for their oil. But worries extend also to the United States with a chronic trade deficit and dollar problem.

For the long run, beginning in another 10 years, the major threat, according to the report, is a precipitate rise in oil prices as world production levels off, exacerbating the financial problems of the medium-term period.

"The danger in the longer term is not that of a price increase per se," the authors say, "but that a large increase could occur in such a short time period that the world economies would be unable to adjust, and recession or even depression could ensue."

To avoid such an abrupt rise in prices, the authors put forward the strategy of consciously boosting prices now, so as to discourage consumption and to encourage alternative supplies such as liquefield and gasified coal, oil from shale, etc.

They attribute their more optimistic supply picture of the moment to higher forecasts of oil yields from Mexico and other new areas under development, but also to a slowdown in the rate of growth of energy demand.

That is labeled a serious development, and the authors call for political leaders in Japan, the United States, Canada, and Europe "to underscore the point that economic stagnation is a poor solution to the energy problem."

The report points out that unless economic growth continues at a good pace in the industrial world, the necessary investment capital to develop alternate sources of energy won't be forthcoming. The authors say that the relationship between energy and economic policy should be an important agenda item from an energy summit.

"Decisive action now would reduce the risks associated with another 'off shock'," the report says. But "five more years of indecisiveness would . . . increase the likelihood of major disruptions to the world's political and economic system in the interim."