Neil Lennon has spent the last couple of years building a strong talent pool.
He has another opportunity to strengthen when the January transfer window opens in a fortnight but assistant manager Mjallby said: "We are quite happy with the players we have got.
"If the opportunity arises I am sure the manager and the chief executive will sit down and have a discussion.
"You always want to improve your squad and bring new faces in.
"What matters is that if you bring a player in, he needs to be of top quality and someone that is going to strengthen us."
Saturday's home win over St Mirren ensured Celtic kept their four-point advantage at the top of the SPL.
It was an overdue home triumph and Mjallby wants his side to hit Parkhead the goal trail in the coming weeks.
He said: "We have got four games coming up now before we break and our target is to try and win them all.
"We were a bit surprised that we were maybe not doing as well at home as we were away and we were dropping points here and there.
"We didn't want to use the excuse that we were focusing on the Champions League.
"I still don't think that was really the reason why we weren't doing well. We were playing against teams who were sitting in and making it hard for us.
"I think we are improving so even if teams come to Celtic Park and sit in and defend, we can improve the way we open up teams and start banging in a few more goals.
"In the last two games, we have got two wins so we are getting there."