The midfielder, who scored in the 4-1 win against Sunderland in the Premier League on Saturday, is out of contract at the end of the season.
However, Gunners boss Wenger claims that an agreement has been reached that will see the former Borussia Dortmund star stay at the Emirates Stadium.
"Tomas Rosicky will stay. We have an agreement with him and it will come out soon. I am absolutely adamant he has to stay at the club," the Frenchman is quoted as saying by Sky Sports News.
"He is maybe one of the players who plays the game of give and move, is a great accelerator of the game."
Rosicky, 33, joined the club in 2006.