Sinn Fein members have been told Gerry Adams is a central part of the party's government formation negotiating team.
In a briefing note, Mr Adams is listed along with other unelected party members Martin Lynch, Dawn Doyle, Stephen McGlade and Ken O'Connell as part of the team.
The party publicly announced its negotiating team would be led by Pearse Doherty and include Eoin O Broin, Louise O'Reilly and Matt Carthy.
Mr Adams attended the ard chomhairle meeting where the negotiating team was decided. However, his appointment was not publicised.
"Sinn Fein has many experienced negotiators and we will draw on that experience as required," a Sinn Fein spokesperson said.
A Sinn Fein source said Mr Adams has been involved in a negotiations for "most of his life" and this was the reason he is involved in the talks.
Mr Adams sat in the Dail's visitors gallery during the vote for Taoiseach yesterday along with other party supporters.
He played a low-key role during the general election campaign but has been attending party events since the vote.
The controversial politician resigned as Sinn Fein leader in 2017 and did not run for the Dail in the recent election.
He has been questioned by gardai and the PSNI about murders by the Provisional IRA during the Troubles.
He claims he was not a member of the terrorist organisation.
The Sinn Fein memo, which is signed by the party's deputy leader Pearse Doherty, also warns members to be ready for another general election.
Mr Doherty said if it is not possible to form a traditional government a minority government or a confidence and supply agreement may be put in place.
"If none of this is possible a second election could take place and we need to be prepared for this," he added.
Mr Doherty said Sinn Fein has to "stay true to the politics and messages we fought the general election campaign on".
This includes continuing to push its slogan of giving "workers and families a break".
He also said the party should focus on a "small number of key issues", including seeking Irish unity, cutting rents and freezing them, building homes, restoring the pension age to 65 and taking the first €30,000 people earn out of the USC.
"Our voters need to get the message from our approach and publicity around any negotiations that we are seriously committed to delivering the kind of transformative change they are looking for and that we will live by the commitments we have made," he said.
Mr Doherty said the Sinn Fein ard chomhairle has "directed the negotiations team to establish whether a credible programme for government can be negotiated".
"This would allow the ard chomhairle to recommend to an ard fheis whether we go into government. There will be no such initiative without ard fheis authorisation," he added.
Mr Doherty has been leading negotiations for Sinn Fein and has held talks with the Social Democrats, the Green Party and Solidarity-People Before Profit.
Meanwhile, Fianna Fail leader Micheal Martin launched a scathing attack on Sinn Fein leader Mary Lou McDonald during a Dail vote for the next Taoiseach.
Mr Martin said he could not go into go into government with Sinn Fein because of the party's "efforts to legitimise a murderous sectarian campaign" of the Provisional IRA.
"Every single time an issue arises about the behaviour of people associated with the Provisionals movement and today's Sinn Fein the response is to attack and dismiss," Mr Martin said.
"Only when the evidence keeps piling up and the political pressure grows is there any movement.
"Offers to meet are expressed and calls for co-operation with law enforcement are issued - but nothing ever happens."
Mr Martin said the "glorifying of the Provisional IRA isn't an accident of one deputy's exuberance" in reference to Sinn Fein TD David Cullinane saying "up the 'RA" at a post- election event.
He said Ms McDonald "praised Provisional IRA units" and she ends speeches with "Tiocfaidh ar la".
"She knows full and well what the use of that phrase means. Popularised first by Gerry Adams, for decades it was shouted in our courts to signal a refusal to recognise this democratic republic," he added.
Ms McDonald responded by saying that she "did not care" what Mr Martin thinks about her party.
She said Sinn Fein lives "rent-free in Micheal Martin's narrow and bitter mind".
Ms McDonald added that Mr Martin sat around the cabinet table with people who have been jailed for corruption.