Striker Franco di Santo and defenders Antolin Alcaraz and Maynor Figueroa are the most high-profile of those whose current deals expire next summer.
But Jackson said negotiations had been on-going for some time and he was not too concerned they had not yet been tied down to new contracts.
"There is a lot of time before that would ever become a major concern," he told the Wigan Evening Post. "We have been talking with some players who are coming up to the end of their contracts now for 18 months and that will continue.
"It would be unfair for me to comment too much at this stage because it's still early but we're not unduly concerned.
"At the moment we're just concentrating on getting off to a great start in the league and whatever will happen will happen."
- Maynor Figueroa
- Antolin Alcaraz
- Wigan Evening Post
- Franco di Santo