The result of a planned private sector Greek debt swap remains uncertain, French bank BNP Paribas' Greek debt negotiator told Le Monde newspaper in an interview published on Wednesday.

It is impossible to be certain of the outcome of such a process, Jean Lemierre told the newspaper. But the success of the offer is in everyone's interest.

Greece and the European Union would likely revise some of the terms of the deal if it lost its voluntary character, Lemierre said.

He added that a disorderly Greek default would have very serious consequences for the euro zone, including the possibility of contagion reaching other weak countries in the region.

(Reporting by Lionel Laurent; Editing by James Regan)

BNP Paribas