Kaka has warned Manchester City that their summer spending may not bring the success the club craves.

City's mega rich Arab owners are in the midst of a shopping spree that has already seen Gareth Barry and Roque Santa Cruz arrive at Eastlands.

They are set to further add to their pre-season transfer haul by acquiring the services of Samuel Eto'o and Manchester United reject Carlos Tevez in the next few days.

Kaka himself was a target for City last January before opting to stay at AC Milan and subsequently making a then world record transfer to Real Madrid.

Despite many observers already decreeing that City are fast becoming a force to be reckoned with, Kaka remains far from convinced that their approach is destined to succeed, a key factor behind his decision to say no to City boss Mark Hughes

"I was very flattered by Manchester City's interest in January but it is just a project at the moment. And with projects sometimes you don't know how long the investment will be there for," he said.

"Lots of smaller clubs have periods of spending big money. But suddenly the investment stops when the owner decides to do something else. Or sometimes it stops because of other reasons like a failing economy.

"Things can be great one moment and not so great the next moment. The organisation can collapse like a pack of playing cards. I felt the time was right for a change and Real Madrid is the club for me.

"It was not about a difference of quality between the Primera Liga and the Premier League. Real will always be a big club. Nobody can take away their history and their nine European Cups."