The Australian dollar has declined after the Reserve Bank of Australia unexpectedly doubled the size of its bond buying program and said interest rates will remain at ultra low levels for another three years.

In a "dovish surprise" the RBA said it would buy another $100 billion bonds - or $5 billion a week - keeping its fast-paced buying for another six months. Interest rates, the three-year government bond yield, and the term funding facility were all pinned at 0.1 per cent for another month.

Sarah Turner has the full story and strategists' reactions on the implications for the Aussie dollar here.