Egypt's main opposition umbrella group, the National Salvation Front, has announced it will boycott the upcoming parliamentary elections on the grounds that the elections law under which they are being held is unconstitutional.

The decision to boycott the election, which was announced on Tuesday by Sameh Ashour, a leading figure from the NSF and head of the lawyers syndicate, was made unanimously during an NSF meeting held on the same day, said Ashour.

On 18 February, the High Constitutional Court (HCC) ruled that as many as ten articles of two draft laws regulating parliamentary polls run counter to the newly-approved constitution. However, the Islamist-led upper house of Parliament passed the law as is without amendment, despite the HCC's ruling.

Ashour also said that the government also did not show its intention to provide guarantees that the electoral process will be fair.

During the past week, reports circulated that were internal disagreements between the groups that make up the NSF coalition on whether or not to participate in the elections.

The NSF also decided to boycott a national dialogue meeting called for by President Mohamed Morsi, describing it as an insult to protesters slain in recent violent clashes.

"No dialogue should be held over the dead bodies of our martyrs," Ashour said at the press conference.

Last week, the NSF announced a set of pre-conditions for dialogue with the presidency, including taking "serious steps" towards the prosecution of those responsible for protesters' deaths by assigning judges to investigate such crimes, along with the formation of a new government of national unity.

The NSF had also insisted on several previous pre-conditions, including the appointment of a new prosecutor-general in accordance with the constitution and judicial independence; amending Egypt's new constitution; postponing upcoming parliamentary polls; and guaranteeing judicial and international oversight of upcoming elections.

The upcoming parliamentary elections will take place over four phases, starting on 22 April and ending on 24 June.