The following table contains the by-elections that have occurred during the term of the 27th Parliament.
| Electorate and by-election | Date | Incumbent | Cause | Winner | |||
|---|---|---|---|---|---|---|---|
| Awarua | 1944 | 28 October | James Hargest | Death | George Herron | ||
| Western Maori | 1945 | 10 February | Toko Ratana | Death | Matiu Ratana | ||
| Hamilton | 1945 | 26 May | Frank Findlay | Death | Hilda Ross | ||
| Dunedin North | 1945 | 21 July | Jim Munro | Death | Robert Walls | ||
| Raglan | 1946 | 5 March | Robert Coulter | Death | Hallyburton Johnstone | ||