On 20 May 1940, with Australia actively involved in the Second World War, Oldfield enlisted in the Australian Imperial Force and served in Egypt, Syria and New Guinea with the HQ Co. 2/16th Battalion.
He was subsequently refused admission to the Parliamentary Party, a move which was not uncontroversial as it was seen as rejecting "unendorsed candidates who had clearly won the confidence of electors".
[1] He sat in Parliament as an "Independent Liberal", and was appointed by the Labor government to a Select Committee inquiring into welfare conditions in the Laverton-Warburton Range area.
In January 1960, Oldfield had joined the Labor Party and was promised unopposed preselection for the 1962 election by opposition leader Albert Hawke.
This meant that the Liberal-Country government could not pass electoral legislation which required a majority on the floor, and the scheduled redistribution took place under the old Act.