The BoI has almost doubled its mortgage tracker rate, affecting more than 13,000 customers, despite the Bank of England base rate remaining at its historic low of 0.5%.
In his letter, Tyrie said he was “very concerned” by the move and queried whether it could be deemed a case of product mis-selling.
He has also asked whether it will be taking a closer look at the clauses within the affected contracts.
From 1 May, the bank will raise the mortgage rate for residential customers from, typically, the Bank of England rate plus 1.75%, to the Bank rate plus 2.49%.
It will then raise it further, to Bank rate plus 3.99%, on 1 October. Buy-to-let customers will see their rate increased to Bank rate plus 4.49% on 1 May.
The BoI blamed the rising cost of providing the mortgages and new rules on the amount of capital it must hold in reserve.