The other method would be through revising the City Charter, which a commission is redrafting.
Others may say that the issue is more properly the business of the commission in place to revise the City Charter.
Mr. Giuliani did not say whether he supported another full-fledged exercise in revising the City Charter.
The lawyers contend that the Council can revise the City Charter as long as it does not tinker with basic government powers.
The proposal for revising the City Charter will be discussed at a closed meeting of the full commission on Thursday.
The commission that revised the City Charter considered giving the Council power to change revenue estimates, and rejected the idea as too risky.
The issue of central versus local control, a staple in government circles, has been expanded and enlivened since a commission began revising the City Charter this spring.
The last three are proposals to revise the City Charter, New York City's version of a constitution.
Voters rejected 14 proposals to revise the City Charter that the mayor had campaigned for as a referendum on his policies.
The City Council does have the authority to revise the City Charter on its own in certain limited instances.