Economic hard times are about to hit New York City’s employees where it hurts: in their driveways.

As the Bloomberg administration scrambles to cut spending, it is ordering city agencies like the police, parks and health departments to give up nearly 700 city-owned cars, a cherished perk for their workers.

The move would save $20 million over the next two years, according to a copy of the memorandum sent to city agencies.

The decision to sell off scores of Toyota Prius cars and Ford Escape sport utility vehicles is very likely to irritate many city workers, who use the them to travel around the city inspecting sites or rushing to meetings. But it would help blunt criticism that City Hall practices a form of vehicular hypocrisy, telling ordinary New Yorkers to use mass transportation while at times clogging the streets with its own city-issued cars.

City agencies must relinquish at least 10 percent, or about 685, of their 6,800 nonemergency vehicles by the end of March, according to the memo from Mayor Michael R. Bloomberg, which was sent on Wednesday and obtained by The New York Times.