CAIRO: Egypt brought forward the start of parliamentary elections to April 22 on Saturday to defuse a row with the Christian minority, who said the original schedule would conflict with their Easter celebrations.

This should satisfy Coptic Christians, who make up 10 percent of the population. But the rift between Egypt's ruling Islamists and the opposition remained as deep as ever, with one leading liberal politician, Mohamed ElBaradei, saying he would boycott the polls.

The decision by Islamist President Mohamed Mursi to start the four-stage vote five days earlier than scheduled was announced by his spokesman on Facebook.

Islamists, who have won every election since the 2011 overthrow of autocrat Hosni Mubarak, dismissed any suggestion that the parliamentary polls would lack credibility and predicted a strong turnout.

Mursi called the lower house elections on Thursday, aiming to conclude Egypt's turbulent transition to democracy.

However, ElBaradei, a former U.N. nuclear agency chief, drew comparisons with the last parliamentary polls to be held under Mubarak in 2010, a vote which was widely seen as rigged.

ElBaradei noted he had called for a boycott in 2010 "to expose sham democracy".

"Today I repeat my call, (I) will not be part of an act of deception," he said on his Twitter account. ElBaradei boycotted the presidential election that brought Mursi to power last June.

The Muslim Brotherhood, which backs Mursi, rejected any call to boycott the voting which has been scheduled in four stages from April 27 to June. Essam Erian, a senior member of the Brotherhood's Freedom and Justice Party, said the polls would be carried out under "complete judicial supervision" as well as being followed by Egyptian, regional and international media.

Voting would be monitored by Egyptian and foreign civil society and human rights organisations, he said on his Facebook page, adding that he expected wide participation.

Egyptian elections have been supervised by judges since the revolution. The relatively small numbers of judges have required the drawn-out process, allowing them to oversee voting in different regions on different days.

Under the new schedule, voting will be completed on June 24, with the new lower house due to meet on July 2. It aims to avoid making Copts vote during the most important festival of the Christian calendar.

The opposition says Mursi should not have called the elections until a number of disputes had been settled, chiefly a new constitution produced by an Islamist-dominated assembly which contributed to serious street violence last year.

Islamists have used well-organised campaign operations to win every election since the revolution, while the liberal and leftist opposition has been beset by divisions. Previous opposition boycott threats have failed to materialise.

The National Salvation Front (NSF), which groups a number of parties opposed to the Islamists including ElBaradei's, is due to decide in the coming week whether to join a boycott.

"This is Dr. ElBaradei's own position and own opinion," said NSF spokesman Khaled Dawood, but he added that other NSF leaders were sympathetic to the idea of a boycott.

"This is yet another individual move by the Muslim Brotherhood and President Mursi, establishing facts on the ground and then asking you to basically go with the rules of the game they've set on their own," he said.