Scott Morrison will replace outgoing Treasurer Joe Hockey, who has announced he will leave parliament following the change in leadership of the Liberal Party.
Former assistant treasurer Josh Frydenberg has been promoted to cabinet with responsibility for Resources, Energy, and Northern Australia.
Ms O'Dwyer moves into the Assistant Treasurer role having held the role of Parliamentary Secretary to the Treasurer in the Abbott government since December 2014.
Alex Hawke will step into Ms O'Dwyer's role as the new Assistant Minister to the Treasurer (as the title 'Parliamentary Secretary' has been scrapped).
Australian Institute of Superannuation Trustees chief executive Tom Garcia welcomed Mr Morrison and Ms Dwyer to the roles, noting the changes see "the return of superannuation and the financial services portfolio to the cabinet".
"Elevating the financial services portfolio to Cabinet recognises the key role superannuation plays in the Australian economy," said Mr Garcia.
"We need to get the settings right for all Australians, define clear objectives for super and move to a point where we have a world-class retirement income system that ideally has bipartisan political support."
A statement by the Financial Services Council said both Mr Morrison and Ms O'Dwyer have "significant policy experience" that will provide Australia with "much needed reform capability".
"We expect the new Treasury team will hit the ground running during this term to complete the reform agenda established by their predecessors," Andrew Bragg, director of policy and global markets, said.
Mr Bragg listed reforms to reduce superannuation fees, life insurance reform and the finalisation of the China Australia Free Trade Agreement as particularly pressing issues.
