A Montgomery County task force on drinking and driving recommended yesterday that police officers who arrest large numbers of drunken drivers be rewarded with perquisites such as the use of an unmarked car, choice working hours, and certificates from the chief of police.

The 112-page report contained 66 suggestions designed to intensify a campaign that doubled drunk-driving arrests, from 721 in 1980 to 1,473 last year as alcohol-related highway deaths were cut in half, from 36 in l980 to 18 last year.

Other recommendations include:

* Minimum fine of $250 for drunken driving.

* Empower police to seize the license of any driver who refuses to take a test to determine the blood alcohol content.

* Spend $100,000 on overtime to have police inspect establishments that sell alcoholic beverages to insure they are not selling to underage or intoxicated customers.

* Return half of all fines collected for drunken-driving offenses to local governments to pay for enforcement and prevention programs.

* Require use of seat belts and child restraints for passengers age 4 and under.

* Continue the "sobriety checkpoints," the controversial roadblocks at which officers have been stopping motorists since last Halloween to check for intoxicated drivers.

The 29-member task force, appointed last July by County Executive Charles Gilchrist, was composed of representatives of government agencies and private businesses, including beer and wine merchants and restaurants. Chairman Charles Short, an employe of the county's family resources department, predicted that if the recommendations were carried out they would "significantly reduce the rate of drunk driving" in the county.

Two District Court judges have declared that the roadblocks violate the U.S. Constitution, but a Circuit Court judge and state Attorney General Stephen H. Sachs have said they are legal.

"The majority of the citizens who have talked with us after being stopped have been overwhelmingly in favor of sobriety checkpoints," said Montgomery County Police Chief Bernard Crooke, who said he believes the roadblocks are a deterrent. "Officers say they see more wives and girlfriends driving now than ever before."

The proposal for police to seize drivers' licenses was questioned by State's Attorney Andrew L. Sonner, who said it might not be legal.

"I fully support that recommendation, but I think (it) should be based in legislation, rather than the authority of the state's attorney's office," Sonner said. "My inclination is that police might be subjecting themselves to legal action."