Milan were condemned by Vincenzo Montella's men at the weekend for making an offer for the Serbia international that was deemed "unacceptable, certainly late and definitely inopportune."
Yet Galliani, who is also determined to secure the services of CSKA Moscow attacker Keisuke Honda, has denied any wrongdoing from his club.
"We have not committed any impropriety," he told Gazzetta dello Sport. "All we have done is made an offer during the transfer window.
"We haven't done anything wrong."
The attacker has one year left on his contract at the Viola and talks over a new deal have so far been unfruitful, prompting Milan to table a bid believed to be in the region of £6.9 million for the 21-year-old.
Tottenham and Manchester City have also been linked with a move for Ljajic during the close-season but only Milan have made an official bid for the player.