From the 1959 Referendum on the voting system Fianna Fail material looking for a yes vote. They wanted to implement a first past the post system like the one that exists in the UK. The real point of the exercise was to enable Fianna Fail to get an overall majority, yet this wasn’t used in their official arguements listed here.
The Referendum was defeated by a narrow enough margin of 51.79% of voters voting No and 48.21% voting Yes.
In 1968 a similar Referendum was held on changing the voting system which was again rejected by voters.