Critics fear Abdoulaye Wade (l) will make his son (r) vice-president Senegalese MPs are due to vote on proposed changes to the constitution which have sparked national protests.
The opposition has called for further demonstrations outside parliament in the capital, Dakar.
The changes would reduce the proportion of votes needed to win a presidential election, and avoid a run-off, from more than 50% to 25%.
Critics say the amendments are designed to ensure that President Abdoulaye Wade, 85, is re-elected next year.
Mr Wade first came to power in democratic polls more than a decade ago but he is now facing growing anger at daily electricity cuts and the rising cost of living.
The bill also creates the position of a vice-president who would be elected in the same polls.
BBC West Africa correspondent Thomas Fessy says many people fear that Mr Wade intends to give the role to his son Karim, who is already a powerful minister in the current administration.
They fear that Mr Wade, 85, would then step down and hand power to his son.
Earlier this week, riot police clashed with protesters while the world-famous singer Senegalese Youssou Ndour urged the government to “see sense”.
This article is from the BBC News website. © British Broadcasting Corporation, The BBC is not responsible for the content of external internet sites.