It comes as the English and Welsh football associations formally withdrew their support for Infantino as the pressure continues to mount on the FIFA president.
Infantino's secretive proposal to raise $4.2 billion from investors including the New York investment firm of Joshua Kushner - brother of US President Donald Trump's son-in-law Jared Kushner - was dropped on Saturday, days after the revelation in media reports provoked a global furore.
UEFA led the backlash and on Thursday its 55 member federations agreed to boycott all FIFA events and competitions while the proposal was active.
Now lawyers for UEFA have informed FIFA that the European body is "actively considering legal action, arbitration, and/or regulatory complaints ... arising out of and in connection with the FFE (FIFA Forward Enterprise) plan proposed by FIFA and all related matters".
The letter, seen on Monday by The Associated Press, named 18 FIFA executives who it said should retain data, documents and electronic messages as potential evidence.
On Saturday, UEFA signalled it wanted to end Infantino's decade-long presidency, saying he had lost the confidence of world football.
Hours earlier, Infantino withdrew the divisive proposal that offered FIFA's 211 member federations one-off payments of $20 million each with a mid-September deadline to accept.
The FFE spin-off valued by FIFA at $20 billion would have taken control of the football body's money-making commercial and tournament operations. The 211 members already effectively own the Zurich-based not-for-profit governing body.
It was the project of just one man, FIFA's chief operating officer Kevin Lamour said in a stinging statement on Friday to the AP which said staff felt deceived by their boss Infantino.
Legal proceedings are "reasonably anticipated," UEFA's lawyer Andrew J Levander wrote, citing the belief of the sport's stakeholders that the plan was "fundamentally incompatible with the proper governance of football".
The English FA is understood to be writing to FIFA making it clear Infantino no longer has its support, while the Football Association of Wales became the first country to publicly withdraw support for the Swiss.
An FAW statement said: "The recent failures in good governance, processes, leadership, values, stakeholder management, communications and sound judgement have led us to a position where Mr Infantino has lost the confidence of the FAW to remain at the helm of world football.
"Failing to put the best interests of football first is a failure we cannot accept."
UEFA has been most outspoken against its former employee Infantino while the Asian Football Confederation and CONCACAF, the North and Central American and Caribbean football body, also have made strong statements opposing Infantino's plan.
Infantino has most support from his traditional base in Africa, while South America's CONMEBOL wants him to expand the 2030 World Cup to 64 teams from 48.
The private equity plan has provoked a stunning turnaround in fortunes for Infantino who left New York after the World Cup final two weeks ago seemingly a lock to be re-elected unopposed next March for a fourth and final term in office through 2031.
- With PA
