Iker Casillas, the Real Madrid goalkeeper, has rejected an £129million offer from Manchester City, according to reports in Spain.

The Premier League club reportedly offered Casillas a £12m-a-year contract which the player immediately dismissed. Cadena Ser, a Spanish radio station, went on to claim that City had made direct contact with Luis Garcia Aba, Casillas's agent, but the offer was not forwarded to Real because the player had rejected the approach out of hand.

However, Garry Cook, City's executive chairman, while not denying the reports, has warned the club is taking a careful approach to its transfer dealings.

“Manchester City Football Club has a clear strategy for the future. We want the right players who will take this club forward and through discussions and meetings between myself, Mark Hughes and his technical staff, we have identified a list of targets," he told GuillemBalague.com.

"We will be working to bring those players to the club ourselves and we have not given another party or individual a mandate to negotiate on our behalf: in spite of recent reports, we are not using intermediaries to negotiate with players. In fact, only last week we refused two agents permission to seek out players on our behalf.

"Mark Hughes and I very recently met with the Chairman, Khaldoon Al Mubarak, to discuss this matter and we are all in agreement: that the mandate for seeking out and securing new playing personnel for Manchester City Football club is ours and ours alone. Furthermore, we would also like to assure everyone concerned that we are committed to recruiting only those players who we consider to be the very best and most suitable for Manchester City Football Club in the future.”

Casillas, 27, is widely regarded as one of the world's best goalkeepers and played a leading role in Spain's Euro 2008 victory. His current deal at Real runs until the 2016-17 season, but is thought to have a buyout clause which City's bid would have triggered. Any transfer fee for Casillas would smash the world-record figure of £48m that Real Madrid paid Juventus for Zinédine Zidane in 2001.

Casillas is the latest big name to be linked with City after reports last week that the club's wealthy Arab owners had launched a £50m bid to sign Gianluigi Buffon, the Juventus goalkeeper.

Having broken the British transfer record by signing Robinho from Real Madrid for £34.2m on September 1, the day that they bought the club, City's owners, the Abu Dhabi United Group, could are expected to go even further when the transfer window re-opens in January.