The Austrian has been a mainstay in the German champions' team for the past several seasons.
But he has less than a year left on his deal, and so far negotiations have not gone smoothly.
Bayern would loathe to lose Alaba for a cheap fee this summer or on a free next summer.
However, chief executive Karl-Heinz Rummenigge is optimistic at finding a positive end to talks.
"With Alaba, I am cautiously optimistic we will find a solution," Rummenigge told the media on Tuesday.