The Blues have spent more than £30m this month already, but Koeman says he hopes to add more quality to the side in the coming weeks.
He did, however, add that it can be difficult to sign players in January who will be available in the summer.
When asked if the club would be bringing more players in this month, he said, “I hope so.
“We are working on that but only when we get players with the quality to make the team stronger. I’m not bringing players in just to get more numbers.
“That’s not what I like.
“It’s difficult in January because maybe you’re interested in players who can’t leave their club until the summer.”