Benitez is one of the leading contenders to take the Celtic Park job this summer amid rumours he will leave St James’ Park when his contract expires at the end of the season.
The Spaniard, who has previously managed Liverpool, Chelsea and Real Madrid, is not getting the assurances he has asked for from Mike Ashley, the Newcastle owner, and many clubs will be looking at Benitez this summer should he depart the Magpies.
Celtic are understood to be one of those clubs, with Hoops chiefs on the lookout for a new manager to become the long-term replacement for Brendan Rodgers.
Rodgers departed Celtic Park last month to succeed Claude Puel as Leicester manager, with Neil Lennon returning to Glasgow as Rodgers’ replacement on a deal which runs until the end of the season.