Monaco only gained promotion from the second tier at the end of last term but their ambitious summer spending spree has fuelled talk that they could compete for top spot.
Radamel Falcao, Joao Moutinho and James Rodriguez are among those to have joined the club during the transfer window.
Ranieri, however, says his main focus will be on getting his new-look team to gel and believes there are other sides better equipped to push reigning champions Paris St Germain.
"Compete with PSG? I believe it is too early to ask such a question," Ranieri told L'Equipe.
"PSG, Lyon and Marseille look more like teams than Monaco. So we need time. It will be difficult to be champions this season.
"Give me some time. To me the most important thing is first to try to build the best group possible."