Canadian officials have "serious reservations" about plans for the final two years of a major American acid-rain study, saying it appears researchers already have concluded immediate cuts in pollution are not needed.

At a public hearing about the study outline Thursday, a top environmental official from Canada criticized what he called "a priori conclusions and biases" in the 1989-1990 plan for the 10-year National Acid Precipitation Assessment Program, which is expected to issue a final report in September 1990 containing recommendations for Congress.Hans Martin, acid-rain researcher with the Atmospheric Environment Service of Environment Canada, also charged the planning document placed too much importance on technical uncertainties and "information gaps," distorting the overall picture presented by most data.

Martin said the planning document was an improvement over the 1987 interim report by the NAPAP, which was criticized by scientists for unduly discounting the environmental threat posed by acid rain. However, Martin stressed, "Canada still has serious reservations."

In his view, "Without substantial changes in the plan's approach, NAPAP will not be able to provide decision-makers with complete, comprehensive and sound information."

Paul Heinbecker, political minister at the Canadian embassy, said Canadians were encouraged by Vice President George Bush's statements during his White House campaign in support of acid-rain control.

But Heinbecker said Canadian officials were dismayed by the planning paper's repeated statements that major information gaps likely would remain after the study is concluded.

"Policy cannot be held hostage to gaps in our knowledge when there is a public consensus that action is needed," Heinbecker said.

President Reagan's administration has opposed acid-rain control measures for eight years, insisting more research is needed to resolve uncertainties about the link between the product of industrial emission and environmental damage.

Sulfur dioxide emissions from coal-fired power plants in the United States are believed by scientists to be the principal cause of acid rain that falls in the Northeast and Canada.

Martin said one example of "bias" in the planning document was a statement that ozone - not acid rain - was probably the cause of damage to agricultural crops. He said that statement ignored the possible role played by acid rain in leaching key nutrients out of certain soils.

More broadly, Martin questioned the plan's heavy emphasis on researching the implications of delaying emission reductions until more efficient pollution control technology is fully developed.

"This question does not reflect the costs inherent in waiting for new technology," Martin said.

The idea of waiting for better technology mirrors the lobbying of the U.S. electric utility industry, which has urged Congress to hold off on acid-rain legislation until new ways of controlling pollution can be widely deployed, probably in the 1990s.

Utilities contend new "clean coal" technology will be more effective and cheaper than the smokestack "scrubber" units now available. Environmentalists counter that utilities are simply trying to delay spending money on controls.