"Strange thing for a father to do to his daughter," one user wrote.
Foster appeared to attempt to stop the backlash by confirming it was his child.
"Was very special for all the players to have our children share tonight's experience as mascots. My beautiful 8 yo daughter. Unforgettable," he wrote on Twitter following the backlash.
"Shame my 16 yo girl and 18yo son couldn't be there as well. I certainly would have hugged them very close too. Special for a father.
"My wife was there, as well as extended family."
Not all the comments on social media were critical. "Can't be affectionate toward your own kid any more," posted one fan on Twitter.
Foster was playing alongside former Socceroos stars for the Australian Legends XI in last night's clash with the Liverpool Legends before a crowd of 40,815 at Sydney's ANZ Stadium.
Despite the Legends winning 4-0, discussion of the game was eclipsed by the furore over Foster's hand gesture.
In the footage, he's seen standing shoulder to shoulder with other Ex-Socceroos, with their children forming a row in front.
Foster, who is married to wife Lara, is also is a mentor at his former school Kadina High in Goonellabah, NSW.
He played with Portsmouth and Crystal Palace in England before heading back to Australia ahead of his retirement from professional football in 2003.
The 46-year-old made 29 appearances for the Socceroos before hanging up his professional boots and becoming a sports commentator with SBS.
-News.com.au
