Massachusetts juveniles ­incarcerated for life without ­parole will probably wait well into 2013 or beyond for a chance at reduced prison time, as lawyers, prosecutors, legislators, and advocates carefully craft a strategy to bring the state into compliance with new federal law outlawing the mandatory sentence.

Massachusetts has not been as quick to act as states such as North Carolina and Iowa, which have implemented new laws since June, when the US Supreme Court banned mandatory life without parole for ­juveniles convicted of murder. While change is expected in Massachusetts, either through the courts or legislation, no clear answers have emerged on how to handle new cases and review past convictions involving killers under 18.