According to the Football411.com website, the midfielder joined Downs in January 2011 from Orlando Pirates, yet has been linked with Kaizer Chiefs amidst talk he has signed a pre-contract with Amakhosi.
Modise, however, has told Football411 that he will be staying put in Chloorkop.
"Firstly, my contract with Sundowns ends at the end of next season which means I'm still a Sundowns player until the end of the 2013/14 season," he said.
"That's why I don't understand why people are saying it ends this season."
The 30-year-old has confirmed that he is in fact negotiating a new contract with the Brazilians.
Modise explained: "We are negotiating at the moment because obviously we have to check now what's going to happen at the end of next season, but I will still be at Sundowns at least until then because I'm still contracted to the club.
"Sundowns had an option on my original contract which was for two more years after the first two so Sundowns took that option last season.
"So now as I said my contract will expire at the end of 2013/14."