Tánaiste Leo Varadkar has admitted Fine Gael volunteers and students have also posed as pollsters to get the opinion of voters
It comes after it emerged that Sinn Féin provided members with fake IDs and instructions on how to pose as researchers from a polling company while knocking on doors around the country.
The polling company in question - the Irish Market Research Agency - does not exist, the Irish Independent reported today.
Sinn Féin has defended the now-discontinued practice, with Eoin Ó Broin insisting there was “nothing untoward” about it.
Fianna Fáil's Marc MacSharry has said gardaí should look into what happened.
However, Fianna Fáil this evening also admitted its party members previously posed as market researchers to secretly survey voters.
In a statement, they said: "Since 2007, the Party has outsourced polling to private, independent providers.
"Prior to 2007, we did on occasion use party members to undertake polling and on those occasions they did pose as market researchers. This was to supplement private providers also used. This practise was ended around 2007."
On RTÉ Radio this evening, meanwhile, the Tánaiste acknowledged Fine Gael had carried out a similar practice before he became leader.
He said: "This isn't something that we've done since 2016... but certainly prior to that, we would have done something similar. They’d be either volunteers or students.”
He said the process would have been “anonymised for the purposes of polling”.
Ahead of Mr Varadkar's comments, his party colleague Simon Harris told The Hard Shoulder that the Sinn Féin practice sounded “bizarre at best”.
He said: “Parties engage in opinion polls all the time… there’s nothing wrong with anybody from Sinn Féin or any other party knocking on a door asking people their views on issues.
“But the lengths they seem to have gone through with fake ID badges and instructions on how to effectively misrepresent themselves… does seem bizarre, to be polite.
“I think it sounds a bit sinister, and they need to answer for it.”
Asked about whether his own party was engaged in the practice, he said: “As somebody who has been involved in elected politics for 10 years, I’m certainly not aware of anything like that ever happening in any political party… I wasn’t even expecting Sinn Féin to be up to this.”