ALBANY, N.Y. - New York Mayor Michael R. Bloomberg said Monday he would support a proposal by Governor Andrew M. Cuomo to significantly curb the number of people who could be arrested for marijuana possession as a result of police stops.

Cuomo plans to urge lawmakers to change state law to decriminalize possession of small amounts of marijuana in public view, an offense that critics say leads to unfair charges against thousands of people who are ordered to empty their pockets during police stops that have proliferated under the Bloomberg administration’s stop-and-frisk practice.

Bloomberg, whose administration had previously defended low-level marijuana arrests as a way to deter more serious crime, said in a statement the governor’s proposal “strikes the right balance’’ in part because it would still allow the police to arrest people who were smoking marijuana in public.

Cuomo, a Democrat, announced his plans to seek the change in state law at a news conference at the Capitol Monday.

The governor said he would seek to downgrade the possession of 25 grams or less of marijuana in public view from a misdemeanor to a violation, with a maximum fine of $100 for first-time offenders.

Raymond W. Kelly, New York City police commissioner, attended the news conference as a way of demonstrating the city’s support for Cuomo’s proposal.

Echoing the mayor, he described the governor’s proposal as a balanced approach.