The head of one of largest mortgage broking firms is questioning an interest rate hike by our largest bank

ANZ's lifted its rate 10 basis points to 5.79 percent - bringing it in line with most competitors, but well above its one-year fixed-term rate of 4.49 percent.

The bank says it's responding to market conditions.

But Squirrel Chief Executive David Cunningham says it will impact anyone who doesn't renew or refinance straight away.

He says even he rolled over to a higher floating rate last year, after forgetting to renew - and that bolsters bank profits.