After the Rossoneri made a reported bid of 8million euros for the Serbia attacking midfielder, whose contract expires at the end of the 2013-14 Serie A season, Fiorentina issued a statement through their official website that described the offer as "most certainly late and definitely inopportune".
Galliani, however, feels Milan are well within their rights to move for the player while the summer transfer window - which does not close until September 2 - remains open.
He told the Corriere dello Sport: "We haven't done anything wrong. We aren't barred from making an offer in the transfer window."
Reports in Italy suggest one-time Manchester United trialist Ljajic, 21, has already held contract talks at San Siro but Galliani rejected those rumours today.
"At this moment I would say the conditions are not in place to complete a deal," he added.
Ljajic has scored 17 goals in 86 appearances for La Viola since arriving in Florence from Partizan Belgrade in 2010.