KUALA LUMPUR, Malaysia - Tun Dr Mahathir Mohamad is not convinced with former Selangor Mentri Besar Datuk Seri Dr Mohamad Khir Toyo's claim that his controversial mansion costs only RM3.5mil.

"He cannot simply say he bought the mansion for RM3.5mil. I believe it is more than that," he said.

"I also have a home in Seri Kembangan. I have spent RM1mil on it, but this (Dr Khir's mansion) is massive - many times bigger than mine," he said.

Dr Mahathir was met by reporters after attending a closed-door meeting on the position of the institutional monarchy and the Malays in the Federal Constitution from the 1Malaysia perspective at the Putra World Trade Centre, here, yesterday.

Asked if the matter could tarnish Umno's image, he said: "Yes, I think so. He has to explain where he got the money to buy the house."

On Monday, Sekinchan assemblyman Ng Suee Lim alleged that Dr Khir's property was worth RM24mil, but the latter had denied it saying that he secured a RM3.5mil loan to buy the house five years ago.

Mohd Khir said he took the loan from HSBC and had no problem servicing the monthly repayment of RM18,743 as he was now involved in business from which he was making RM50,000 a month.

It was also reported that the Malaysian Anti-Corruption Commission will investigate Ng's allegation that Dr Khir spent RM24mil to build the Balinese-style mansion in Section 7, Shah Alam during his tenure as the Mentri Besar.

MACC chief commissioner Datuk Seri Ahmad Said Hamdan said the commission would get more details from the Selangor government.