It is believed he will call a snap regional election for December, a move that could help break a one-month deadlock between the Madrid government and Catalan separatists seeking independence from Spain.
Further cracks appeared late on Thursday in the secessionist coalition as members backed a vote while others said there was no alternative to independence.
An opinion poll published by the El Periodico newspaper on Sunday showed a snap election would probably have results similar to the last ballot, in 2015, when a coalition of pro-independence parties formed a minority government.
The country was plunged into political turmoil after the October independence referendum in Catalonia which Madrid has branded ‘illegal’.
A formal declaration of independence could see Puigdemont charged with sedition, a crime that carries a 30 year maximum jail term.
Puigdemont is understood to be living alone in the Catalan President’s official residence in Palau de la Generalitat.
The possibility of a formal declaration has increased in recent hours after Catalan vice-president Oriol Junqueras claimed the Spanish government had given independence supporters no option but to “proclaim a new republic”.
Spanish news outlets have reported that Mr Puigdemont’s wife and daughters have fled the country to her native Romania.
Tomorrow Madrid is expected to seize control of the autonomous region and authorise the central government to directly rule the area.