City are keen to add to their strike force after selling Mario Balotelli and Carlos Tevez to AC Milan and Juventus since the start of the year.
The Etihad Stadium side have been strongly linked with Sevilla striker Alvaro Negredo and Fiorentina forward Stevan Jovetic.
With Sergio Aguero yet to link up with the squad’s pre-season trip to South Africa, Edin Dzeko is the only senior forward at Pellegrini’s disposal.
But, having seen his team beaten 2-0 by Supersport in his first game in charge at Loftus Versfeld in Pretoria on Sunday, he is confident that there will be additions before the new campaign begins.
He said: “We are working on new players that can arrive at Manchester City.
“We are not in a hurry to bring them now but we are clear that we need two or three more players.
“It’s important to have a very good squad. I said before we came to South Africa that we needed to play for each position and that’s what we are looking for and I’m sure that we will have it.
“It’s difficult to say a date but before July finishes I think we will have more players.”
Pellegrini has confirmed that Brazilian defender Maicon, who only joined from Inter Milan last summer, is set to leave the club.
The right-back has not travelled to South Africa and is being linked with a move to Serie A side Roma.
Pellegrini said: “Maicon didn’t come here to the pre-season and he will not stay in the squad at Manchester City this year.”
City are next in action against AmaZulu on Thursday.
New signing Jesus Navas and fellow Spain international David Silva will not join their team-mates until the trip to Hong Kong next week but Aguero and fellow Argentina player Pablo Zabaleta are set to join the squad this week.
Pellegrini maintains that results are irrelevant after so little pre-season training.
He added: “We are just starting the season so it’s not always important to win but for us it’s important to give minutes to the whole squad.
“The players were clear with what they had to do in this game. I spoke with them before the match and we had four or five days working and the first match it’s important but not to change all our preparations for the season to give our best in the first game.
“We’re not prepared to play the way we want them to play.”