The fresh opposition came less than a day after interim President Adly Mansour laid out a timetable for elections by early next year and appointed a new prime minister and vice president.
The vice president, Nobel peace laureate Mohamed ElBaradei, was one of Morsi's most ardent opponents.
The National Salvation Front (NSF), the main coalition that called for Morsi's resignation, announced "its rejection of the constitutional decree," in a statement.
The coalition, which was led by ElBaradei before Morsi's overthrow, will seek amendments to the decree, it added, without specifying the offending clauses.
Morsi's Muslim Brotherhood, which insists on the ousted president's reinstatement, has also rejected the interim charter and timetable.
Meanwhile, new premier Hazem al-Beblawi is planning to extend an olive branch to the Muslim Brotherhood by offering them cabinet posts, the official MENA news agency quoted a presidential aide as saying.
The conciliatory move will likely be rejected by the Brotherhood.
The military's ouster of president Morsi a week ago, after massive protests calling for his resignation, has pushed the divided country into a vortex of violence that has already claimed dozens of lives.
In the worst violence since Morsi's overthrow, at least 51 people, most of them supporters of the ousted Islamist, died in clashes outside military barracks in Cairo on Monday.
An official with one of the parties in the NSF told AFP on condition of anonymity that Mansour's 33-article declaration foresees new "legislative, executive and judicial powers" for the interim president.
"You would look like a hypocrite now. It makes it look as if you are not against dictatorship, just against a dictatorship that is not from your group," he said.
The Muslim Brotherhood has called for an "uprising" to restore Morsi, Egypt's first democratically elected president, as the legitimate president.
On the opposing end, Tamarod, the movement that spearheaded the grassroots campaign against Morsi, complained that it had not been consulted on the transition plan announced by Mansour and would also make proposals for changes to the blueprint.
But the army warned it would brook no disruption to what it acknowledged would be a "difficult" transition.
The blueprint unveiled by caretaker president Mansour is intended to replace the controversial draft constitution, suspended on Morsi's ouster.
A committee will be set up to make final improvements to the draft before it is put to a referendum.
Parliamentary elections will then follow within three months and Mansour will announce a date for a presidential election once the new parliament has convened.
BA/BA