"There are problems but I believe that ultimately there won't be any," Fernando Fernandez Tapias told reporters in the city of A Coruna where Real are playing a friendly against Deportivo later on Thursday.
"We thought he would be here but for the moment he is not a Madrid player although possibly he will be."
Asked if Real's bid for the quicksilver Wales winger would be successful, he said: "I believe so but I couldn't swear to it or sign off on it completely. Let's wait and see because it's dragging on".
Bale's move to the nine-times European champions, which media reports have said will create a new world record fee of around 100 million euros (85 million pounds), appeared a formality on Wednesday when Spurs manager Andre Villas-Boas said he expected it to be completed before the window closes on September 2.
However, this is the first time a Real official has acknowledged difficulties in sealing the deal to buy the 24-year-old, voted English Footballer of the Year last season.
"I have no doubts about Bale's quality but Madrid without Bale ... has an amazing team," Tapias said.
(Reporting by Iain Rogers; editing by Tony Jimenez)
