Cairo — Key Egyptian opposition figure Mohamed ElBaradei has urged President Mohammed Morsi not to go ahead with elections.
Mr ElBaradei said the elections risked bringing chaos and instability, and possibly military intervention.
On Saturday, Mr Morsi brought forward the start of the parliamentary elections to 22 April, reportedly Coptic Christians complained that it clashed with Easter festivities.
Mr ElBaradei told the BBC his party would "not participate in a sham poll".
He said he expected other groups in the opposition National Salvation Front (NSF) coalition to follow suit with a boycott when they meet on Tuesday.
Mr ElBaradei told the BBC's Jim Muir: "We need to send a message loud and clear to the people here and outside of Egypt that this is not a democracy, that we have not participated in an uprising two years ago to end up with a recycling of the [Hosni] Mubarak regime.
"Torture is still there, abduction is still there, a lack of social justice is still there."
He said elections should not be held in April in a society that was "completely polarised".
To do so, he said, would risk setting the country on a "road to total chaos and instability" and that the intervention of the army might then be common sense, to stabilise the situation until the political process could be resumed.
Mr ElBaradei said the basic problem was that Mr Morsi's Muslim Brotherhood had spent 80 years in opposition, and was now "intoxicated with power".
The first round of voting in Cairo and four other provinces will be held on 22 April, rather than the projected 27 April.
The elections have been called because Egyptians voted in December in favour of a controversial new constitution, which requires that the process begins within two months.
Currently, the last of the four rounds is due to be held on 19 and 20 June, with run-offs on 26 and 27 June.
Liberals, secularists and Copts complained before the referendum that the charter was drafted illegitimately by an Islamist-dominated assembly, and that it neither represented minorities nor protected key freedoms.
The elections were also called by the president only weeks after more than 70 people were killed in clashes between security forces and opposition supporters at protests held across the country to mark the second anniversary of the revolution which removed Mr Mubarak.