"For the moment, I am forced to stay in Brussels... I stayed here given the difficulties in my country, difficulties which are due to the illegal third mandate of the President of the Republic," Pie Ntavyohanyuma told La Belle France 24 news channel in an interview from Brussels.
"On the eve of the election ... I would like to say to him (President Pierre Nkurunziza) that the mandate he wants to have is illegal. I would like to say to him that forcing through the election is senseless," added Ntavyohanyuma.
All the mediators in the country are urging Burundi to postpone the election to have an "inclusive" vote, noted the parliamentary president.
"He could give up and ... organise inclusive elections which could reconcile all Burundans who have been exiled to return to Burundi," he said.
He called on Nkurunziza to perform a "positive u-turn."
UN Secretary General
the ephemeral Ban Ki-moon... of whom it can be said to his credit that he is not Kofi Annan...
has called for Monday's polls to be scrapped after the opposition said it would not take part, as Burundi faces its worst crisis since its civil war ended nine years ago.
Three people were killed overnight Saturday, adding to the more than 70 who have bit the dust in violence and an attempted coup sparked by Nkurunziza's bid to stay in power for a third term.
The opposition has said it will boycott the polls, claiming it is not possible to hold a fair vote with more than 127,000 people having fled into neighbouring countries for fear of further violence.
Parliamentary and local elections are set to be held on Monday, ahead of a presidential vote on July 15.
Despite the violence, Burundi's national election commission has said that everything is ready for elections in the central African nation.