A major rupture is understood to have emerged within Sinn Féin over who may be appointed as the next deputy first minister.
It is understood that party president Gerry Adams is anxious to ensure that senior MLA Conor Murphy does not secure the position, instead favouring the younger Mid Ulster MLA Michelle O'Neill.
The former IRA commander yesterday announced his retirement from politics after he emerged he is suffering from a serious illness.
Mr McGuinness, who said he was "physically unable to continue", was instrumental in bringing down the Stormont Assembly amid the bitter row between Sinn Féin and the DUP over the 'cash-for-ash' scandal.
He spoke in detail for the first time about his health battle and revealed that after "a lot of thinking" he will not be contesting the forthcoming election.
But the spotlight has immediately switched to Mr McGuinness's successor, sparking serious tensions internally.
Mr Adams is expected to install one of the party's most prominent female politicians as the next deputy first minister.
Any decision to appoint Ms O'Neill will raise the prospect of Mary Lou McDonald being chosen to replace Mr Adams when he steps aside.