The 67-year-old previously managed Portsmouth, but also took charge of the Saints during their relegation season in 2005.
Redknapp told reporters: "They hate Portsmouth. There's hatred there. I was at Portsmouth - it was my club on the South Coast apart from Bournemouth - so I expect it."
"They were good to me at Southampton. When I was there, the fans were excellent, I didn't have a problem. I went there well into the season and it was tough. But I still enjoyed it."
Redknapp will travel to St Mary's Stadium with his QPR squad on Saturday for the tie that could see Saints go top of the Premier League table.