Washington | Treasurer Josh Frydenberg has left Washington upbeat about challenges facing the global and domestic economies, including a "more positive" outlook for a US-China trade fix, even as the IMF warned Australia must tackle tax reform and that next year's budget may need to tap some of the surplus to stimulate growth.

Mr Frydenberg said his message was "there's no need to panic" and that the global economy "remains sound", after three days of intense talks with counterparts from around the world, including US Treasury Secretary Steven Mnuchin, UK Chancellor of the Exchequer Sajid Javid and India's Nirmala Sitharaman.