City Council members Daniel Dromm and Ydanis Rodriguez introduced a bill Monday to ban horse-drawn carriages from city streets, even as some lawmakers staked out new positions in opposition or signaled fresh hesitation about the legislation.

The bill, which would offer carriage drivers new job opportunities behind the wheel of a green taxicab, faces months of environmental review and committee hearings before it reaches a full council vote.

"Whenever cruelty and endangerment is so clearly documented and brought to our attention, we must act," Dromm (D-Queens) said on the council chamber floor, calling the bill "government stepping in to correct a grave injustice."

Councilman Vincent Ignizio (R-Staten Island), previously undecided on the ban, said he would help the carriage industry fight the ban. "Nobody should be put out of work by city government," he said of the 300 or so carriage drivers.

Councilman Steven Matteo (R-Staten Island) also sided with the drivers for the first time and was among seven council members who stood at a rally outside City Hall with dozens of organized labor representatives and drivers to say the horses are well-treated and livelihoods are at stake.

A similar-sized crowd of animal rights activists rallied at City Hall earlier in the day to thank Mayor Bill de Blasio for his support. Dromm, Rodriguez (D-Manhattan) and two other council members gathered alongside members of groups including New Yorkers for Clean, Livable, and Safe Streets, or NYCLASS.

De Blasio had vowed immediate action to end what he calls an "inhumane" industry but revised his timeline to the end of this year.

Council Speaker Melissa Mark-Viverito supports a ban.

The bill will be introduced in the transportation committee, led by Rodriguez. Previous carriage industry regulations have gone through the consumer affairs committee, but chairman Rafael Espinal (D-Brooklyn) opposes a ban.

Dromm said he will have the 26 votes needed to pass the bill in the 51-member council. Ignizio argued more members will come out against the proposal.

Many council members polled Monday said they were neutral or undecided.

NYCLASS executive director Allie Feldman said animal rights groups have pledged to secure adoptive homes and "lifetime care" for the 200 horses, if the bill is successful.