A bipartisan panel of former government officials and scholars yesterday criticized President Reagan for being reluctant to invoke a constitutional mechanism to delegate powers to Vice President Bush when he underwent surgery. It recommended that Reagan and future presidents develop written guidelines covering medical procedures that might be temporarily incapacitating.

The report said the White House physician was snubbed during two of Reagan's hospitalizations but should have played a crucial role in deciding when the president was incapable of performing his job.

"This commission has been shocked at the low rank and, sometimes, the seemingly low esteem accorded to the physician -- and not just in the current administration," said the report by the Commission on Presidential Disability and the 25th Amendment. The amendment, ratified in 1967, establishes a procedure allowing the president to temporarily declare himself unable to discharge the duties of office, making the vice president the "acting president."

When Reagan was shot March 30, 1981, senior White House staff members -- without consulting Dr. Daniel Ruge, then White House physician -- decided not to invoke the 25th Amendment, the report said. Before Reagan's cancer surgery July 13, 1985, "the White House staff received inadequate medical information or chose to ignore the information it did receive," the panel said.

Reagan did announce he was passing power to Bush during his cancer surgery, but he specifically announced that he was not invoking the amendment to make the delegation. The commission said that was a mistake and urged that the amendment be invoked any time the president undergoes an operation requiring anesthesia.

"The commission believes that the best course is to make routine the use of this mechanism so that its invocation carries no implications of instability or crisis," said the 32-page report from the White Burkett Miller Center of Public Affairs at the University of Virginia. The panel was headed by former Indiana senator Birch Bayh, a Democrat, and former attorney general Herbert Brownell Jr., a Republican, two principal authors of the amendment.

B.J. Cooper, a White House spokesman, said one reason Reagan decided against invoking the amendment in 1985 was a belief that it was "intended for longer-term disabilities."

Cooper also noted the "close working relationship between the president and Vice President Bush" and said, "We also did not want to tie the hands of future presidents."

Bayh said copies of the report will be sent to all presidential candidates in hopes that the winner of this fall's election will make it part of his transition planning.

The commission, which conducted hearings on the amendment during the past two years, said the next president should develop written guidelines on a mechanism for transition of presidential power to the vice president under various conditions, from a medical emergency to treatment for a chronic ailment.

"Most emphatically this must be done not after the inauguration, but before," the commission said. It also called for publicizing any such protocol to acquaint the public with the procedure and to avoid panic over presidential succession.

Citing the efforts of Edith Bolling Wilson to shield the public from knowledge of the strokes suffered by her husband, President Woodrow Wilson, the panel also said the president's spouse must be aware of the provisions of the 25th Amendment. "The commission cannot and does not suggest any set of rules or code of conduct for future presidential spouses but it does strongly recommend that each be brought into the preparatory transition discussions," the report said.

It also said senior White House staff members need to be given clearer guidance on their roles.

"The White House staff has the most to lose if and when the president relinquishes his powers," the panel said.