Sall's decision to push back the February 25 vote plunged Senegal into a crisis which has seen three dead amid clashes between protester and police.
The Aar Sunu Election (Let's protect our election) collective, which includes some 40 civil, religious and professional groups, has called for a rally in Dakar on Tuesday at 1500 GMT.
Protests pitting youths against the security forces have threatened Senegal's reputation as a haven of stability in West Africa as the region is roiled by coups and unrest.
The United States and European Union have called on the government to restore the original election timetable.
The organisers of Tuesday's march said they had received no information from the authorities as to whether it would be banned.
Possible amnesty
Sall, who has been in office since 2012, is now seeking a way out of the turmoil.
Media have reported the possibility of a new dialogue with the opposition, including anti-establishment firebrand Ousmane Sonko, who fought the state for more than two years before being imprisoned last year.
Some have suggested the possibility of an amnesty for Sonko, his imprisoned second-in-command Bassirou Diomaye Faye and for people detained during unrest in 2021 and 2023.
The government has not commented on the reports.
Parliament backed Sall's suspension of the election until December 15, but only after security forces stormed parliament and detained some opposition deputies.
The vote paved the way for Sall -- whose second term was due to expire in April -- to remain in office until his successor is installed, probably in 2025.
Senegal's opposition has decried the move as a "constitutional coup" and suspects it is part of a plan by the presidential camp to extend Sall's term in office, despite him reiterating that he would not stand again.
Mistrust
Senegal's eight public universities began a two-day strike on Monday in protest over the death of a student during Friday's unrest in the northern city of Saint-Louis, the main higher education union said.
Academics posted a video on social media demanding "the immediate restoration of the electoral timetable" and respect for human rights.
Human Rights Watch said in a statement that at least 271 people were arrested on Friday and Saturday.
"The authorities should release all those held for expressing their political views, ensure the right to freedom of assembly, and end assaults on journalists," the NGO said.
Sall said he postponed the election because of a dispute between parliament and the Constitutional Council over potential candidates barred from running, and over fears of a return to unrest seen in 2021 and 2023.
He has also said he wants to begin a process of "appeasement and reconciliation."
But there are questions over whether his gesture will be accepted by Sonko and Faye.
Experts say that an easing of the tension is almost impossible unless the pair are released from prison and Sonko is allowed to run in the election.
But their party has so far rejected the offer of dialogue.
Faye's representative, Amadou Ba, took to social media to express his mistrust of a possible amnesty law -- which some media have said could be discussed on Wednesday by the Council of Ministers.
"An amnesty law is simply an ordinary law (that) can easily be renounced by a new National Assembly," he said.
Ex-presidents Abdou Diouf and Abdoulaye Wade—the father of one of the disqualified candidates, Karim Wade — called on Sall to organise the "national dialogue he has announced, without delay," according to a letter sent to AFP and attributed to the former leaders.
They also called on youths to "immediately end the violence."
DAKAR - Senegalese civil society and opposition kept up pressure on President Macky Sall ahead of opposition protests Tuesday against his move to delay a presidential election.
Forum