FG and Labour agree 'informal' vote pact for upcoming polls
Labour has been seeking to avoid an official vote transfer pact between the coalition parties.
Fine Gael has far more to gain from picking up second preferences from Labour.
Mr Kenny has now called on Fine Gael supporters to pass on their votes to Labour candidates in next week's local, European and by-elections.
But Tanaiste Eamon Gilmore said he will not be making a similar recommendation, although he did signal his preference for Labour supporters to pass on votes to Fine Gael.
However, he said it was "inevitable" people who support the Coalition would pass votes for their preferences between the parties.
"As the Taoiseach says, we don't have a formal agreement on this. I think it is inevitable that people who are supporters of the Government will continue their transfers to the other party. And I'll be doing that myself," he said.
Mr Kenny said he would be asking Fine Gael voters to then support Labour.
"I'll be advising our supporters to pass on their preference votes to the Labour Party candidates," he said.
Historically, a vote transfer pact is always far more valuable to the larger party – and that would also be likely to apply in these elections.
Transfers from Labour will be vital to Fine Gael in the Ireland South constituency in the European elections, where the party is seeking to win two seats.
Likewise, in the Dublin West and Longford-Westmeath by-elections, Fine Gael is in the hunt for the seats, but Labour won't be in the shake-up, so its second preferences will be important. Labour would only benefit in the European elections in Dublin if Fine Gael had a surplus, which is unlikely.
In the Ireland Midlands-North-West constituency, Fine Gael will take one seat, so the transfers will be less important.
FG would also get more out of an arrangement in the local elections, where it has more candidates in the field and is strong in every part of the country.
Mr Kenny's party was planning to tell its supporters to transfer votes to Labour in the elections, despite being aware of the junior coalition party's desire to go it alone.
Labour has been trying to distance itself from Fine Gael ahead of the elections by pursuing its own agenda and carving out its own identity in Government.
But both parties are expected to struggle to retain seats as they are hit by a voter backlash against the Government in the mid-term elections.
Mr Gilmore said he was going to concentrate on getting Labour supporters to vote for his party's candidates.