CAIRO – A fractious coalition opposed to Egyptian President Mohammed Morsi urged its followers Wednesday to vote “no” on a contentious Islamist-backed draft constitution but threatened to boycott the vote altogether if several conditions are not met.

The opposition coalition, known as the National Salvation Front, also urged Morsi to delay the process of adopting a constitution for two to three months, so that “a national dialogue that is serious and equitable” can be conducted.

In a statement, the group said it was seeking “an agreement over the constitutional project that assures social justice democracy and human rights” and is acceptable “to the general public.”

Opposition leaders said they would urge supporters to boycott the vote slated to start Saturday unless the government guarantees adequate judicial supervision of the process; sufficient security at and outside of polling stations; monitoring of the vote by international observers; completion of the vote in one day; and immediate reporting of the results.

The one-day requirement posed an immediate problem. In Egypt, judges are required to supervise polling sites during elections and referendums. At the moment, some of the country’s most prominent judicial organizations have refused to do so.

Because there are not enough willing judges to cover all the polling sites on one day, Egypt’s electoral commission – called the Higher Electoral Committee – said early Wednesday that voting on the draft charter would take place on two consecutive Saturdays. Ten provinces, including most urban areas, will vote Dec. 15, and the rest are slated to vote Dec. 22. Egyptians living abroad were able to vote at Egyptian embassies starting Wednesday.

The process of drafting the new charter, and the document itself, have revealed a profound gulf in how Egypt’s revolutionaries see themselves and their future, with Islamists who back Morsi on one side and a loose alliance of liberal, secular, Christian and figures from the ousted regime of Hosni Mubarak on the other.