Polling takes place in Colombia tomorrow Sunday for a successor to President Ernesto Samper, who is barred from seeking re-election whenhis term ends in August.

Opinion polls suggest that a former mayor of Bogota, the conservative, Andres Pastrana, is the favorite.

He is followed closely by Horacio Serpa of the governing Liberal Party.

The first Colombian woman foreign minister, Noemi Sanin, has surged in recent surveys.

However, correspondents say it's unlikely that anyone will get more than the fifty per cent needed for a first round win, so there will probably be a run-off on June 21.

NOTE: polls open Sunday 1300 GMT, close 2100 GMT; first results expected 0030 GMT Monday