Nothing to stop bank from raising loan margins?

In June 2010, I took a mortgage that was marketed and signed as having the Singapore interbank offered rate (Sibor) plus 0.65 per cent as the interest rate throughout the loan tenure.

This month, I received a letter stating that Citibank is revising the rate to Sibor plus 0.85 per cent.

When I called the bank, I was told only that it is adjusting to market trends and that the small print in the contract allows for this.

So, the bank has invoked the clause without any good reasons other than it can legally do so. What would stop it then from raising the spread to 1 or even 1.5 per cent next year just because it could?

The Monetary Authority of Singapore or the Consumers Association of Singapore should do something, as this is unfair to consumers.