VATICAN CITY - Pope Benedict XVI may issue a decree to bring forward the start date for a conclave of cardinals to elect his successor to earlier in March, the Vatican said Wednesday.

He may, however, stop short of setting a formal framework for future resignations.

"The pope is considering a Motu Proprio (decree) in the coming days... to clarify a few specific aspects of the apostolic constitution on the conclave," spokesman Federico Lombardi said.

It would be up to the pope to judge whether it was "necessary and opportune" to intervene on when the meeting to elect his own successor should begin, Lombardi said.

Historian Ambrogio Piazzoni said "the pope is the only one who can legislate until the last minute".

The decree would have to come before Benedict formally resigns his powers on February 28 at 1900 GMT. He will become only the second pope to resign of his own free will in the Church's 2,000-year history.

The Apostolic Constitution promulgated in 1996 by Benedict's predecessor, the late pope John Paul II, states the conclave must begin between 15 and 20 days after the start of the popeless "Sede Vacante" ("Vacant Seat") interregnum, usually after the death of a pope.

The delay is normally to allow time for cardinals from around the world to gather in Rome following the death of a pope and to organise the funeral.

The period of mourning is normally set at nine days. -Rappler.com