The former Croatian national team manager revealed that negotiations are underway for the Cameroon international.
“We are in contact but it’s not for the media yet,” Bilic told TalkSport.
“We are not panicking, we are good: if we can find a player, or maximum two, who are going to make us better then we definitely want to do it,” he added.
“We have to like the player, and the player has to be free, or payable and a good investment for the club.
“I’m happy with my squad, the transfer window is still very open and there’s a possibility some players will come and some will go.”
The Lions are on the lookout for a new defensive midfielder following reports linking Felipe Melo with a move to Inter Milan.
Song provided three assists in 28 appearances while on loan at West Ham last season.
The 27-year-old has previously played for Charlton Athletic, Bastia and Barcelona.
Song is currently contracted to Barcelona until 2017 but is expected to leave this summer after falling out of favour with the La Liga champions.
Galatasaray won the league title for the 20th time last season and secured a place in the Champions League group stages.