DEDHAM - The bylaw that would restrict where convicted sex offenders can live and travel within Dedham is now drawing fire from the American Civil Liberties Union of Massachusetts.

Annual Town Meeting approved the bylaw in April and Attorney General Martha Coakley’s office, which must sign off on all articles before they become law, has been scrutinizing the measure since the summer.

In a 15-page letter dated Nov. 28, the ACLU calls on Coakley to withhold approval of the bylaw because it impinges the state’s Sex Offender Registry law and denies convicted sex offenders rights protected by the Massachusetts and U.S. constitutions.

The letter says the law will ‘‘effectively banish’’ convicted sex offenders from town and increase the number who become homeless, transient and difficult for police to track.

‘‘The practical effect of the bylaw is to force residents out of Dedham into adjoining towns and cities, many of which have enacted similar residency restrictions,’’ the letter says, ‘‘creating a population of itinerants whose lives are destabilized by homelessness, unemployment, and inaccessibility to supervision networks.’’

If approved by the attorney general, the bylaw would prohibit convicted Level 2 and Level 3 sex offenders from living within 1,000 feet of a school, day-care center, park, elderly housing facility or church.

It would also prohibit sex offenders convicted of committing a crime against a child from entering a town park or ‘‘loitering’’ within 300 feet of a school, school bus stop, day-care center or playground.

The ACLU letter says the provision prohibiting ‘‘loitering’’ is too vague to accurately define the offense and is one of several areas where the bylaw conflicts with constitutional rights protecting due process.

The letter of opposition comes after the attorney general’s office in November asked the town for a clarification of language in the bylaw and for a second 90-day extension of the review period.

Assistant Town Administrator Nancy Baker said the attorney general’s office asked for clarification of some of the language dealing with penalties and enforcement of the bylaw, which the town has provided.

Harry Pierre, a spokesman for Coakley, said the attorney general’s office had asked the town for additional information about the bylaw, but would not say what potential issues were under review.

While the fate of the town’s attempt to control the risk posed by convicted sex offenders locally is in the hands of the attorney general, a bill currently pending in the state Legislature looks to install some of the same restrictions statewide.

The bill, filed by state Rep. Karyn Polito, R-Shrewsbury, would establish mandatory minimum sentences for people convicted of sex crimes as well as restrictions preventing some sex offenders from residing within 1,000 feet schools, day-care centers or the home of their victim.

Park and Recreation Commission Chairman Donald Reisner, who initiated the move for a sex-offender bylaw, said yesterday that he had heard the attorney general might be waiting to see what happens with the state measure before acting on Dedham’s law.

‘‘If they can do it on the state level, that would be great,’’ Reisner said. ‘‘I’m just glad people are thinking about it.’’