Blues midfielder Toure, a former star at the Nou Camp, believes that continued investment from City's owners will eventually see Roberto Mancini's side prove more than a match for Pep Guardiola's Primera Division pacesetters.
"You cannot compare Barcelona with City right now because Barca are at the top and have top-quality players," he told The Sun. "They have Leo Messi, Xavi, Andres Iniesta and Dani Alves, who are fantastic. But we are still signing new players. In a couple of years we could be better than Barcelona."
He added: "What we need to do is continue to work hard and improve with every game.
"I keep saying to my brother Kolo and my family that City have great players but we need to continue to work hard to become great."
City currently lie third in the Barclays Premier League table, eight points behind leaders Manchester United having played a game more than their rivals.
They are also in the last 16 of the FA Cup and the last 32 of the Europa League.
But Toure, 27, insists the club's only target this campaign is to secure Champions League qualification.
The Ivory Coast international continued: "Our target is still to be in the Champions League next year - that is very important for this club.
"But it will be tough to stay in there because Liverpool are coming and I'm sure Chelsea will be back."