"Seeking to protect Puigdemont's right to be effectively present at the investiture debate, (parliamentary) president Roger Torrent will back a demand for preventive measures before the European Court of Human Rights," read a statement from the regional assembly, where pro-independence parties have a majority.
Puigdemont has been seeking to run the wealthy secessionist region of northeastern Spain from Brussels, as he faces arrest should he return home for fronting an independence campaign Madrid deems anti-constitutional.
Spain's constitutional court has made Puigdemont's investiture conditional on his physical presence in regional capital Barcelona -- but he faces arrest if he returns on charges of sedition and rebellion.
The region of 7.5 million people has been under direct rule from Madrid after Prime Minister Mariano Rajoy dissolved the Catalan parliament last October following an abortive referendum not recognised by Madrid.
A spokesman for Torrent said the assembly would ask the ECHR to "guarantee its political rights and, specifically, Puigdemont's right to political participation" without saying when the request would be made.
The Strasbourg-based court's rulings are binding on signatory states.
The Catalan assembly has also taken its arguments on Puigdemont's rights to the constitutional court to contest the latter's conditions surrounding his investiture.
Last Friday, his party submitted a proposal for a regional law reform that would allow the axed president to govern from Belgium, which Madrid rejects.