He had a heart attack on Friday after giving a speech at the World Arts Meeting in Valencia, according to the event's organisers.
The director's work included the 1968 film A Night a Train which starred French actors Anouk Aimee and Yves Montand.
But Delvaux, who was born in Heverlee near Louvain, began his career as a piano player.
He made his first films for television before moving into feature films.
In 1965 he made Man with Shaved Head about a teacher's secret love for a student, based on a novel by Johan Daisne.
International appeal
His style was labelled magic realism as he shifted between dream and reality.
He also directed film documentaries, including one on the Italian director Federico Fellini.
Delvaux, who was also a screenwriter and actor, competed for the Golden Bear award at the Berlin Film Festival with the film Appointment in Bray in 1971.
In 1988 his film The Abyss competed for the Palm d'Or 1988 in Cannes.
His work also included the film The Beauty and Babel Opera.
"Everybody in Belgian cinema owes something to him," film critic Philippe Reynaert told television station RTBF.
Belgian director Jean-Pierre Dardenne told the RTBF radio network he and his brother Luc would not be in film if it was not for Delvaux.
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