LONDON — Confronted with what they consider a power play by a group of wealthy soccer clubs to promote the Champions League at the expense of national championships, representatives of Europe’s domestic leagues will meet in Lisbon this week to discuss a strategy to protect what they say is decades of tradition, and a basic sense of fairness.

What the leagues fear, several officials said, is what they consider a behind-the-scenes campaign to reshape European soccer for the exclusive benefit of the continent’s biggest clubs. The leagues contend the proposed changes to the Champions League, which include new barriers to entry for nonelite clubs and schedule changes that would push matches onto weekend dates, will diminish the relevance and marketability of domestic leagues, and potentially render many of their matches irrelevant.

At this week’s Lisbon meeting, an annual gathering of the umbrella European Leagues group, members will discuss plans to fight back — perhaps even in court — against suggested changes that they argue will adversely affect the competitions that still form the cultural and financial backbone of the global soccer industry. The coalition of leagues is a diverse group — leagues from Portugal to Ukraine are members — but a potentially formidable one given the influence and resources of members like England’s Premier League, Germany’s Bundesliga and Spain’s La Liga.

“The association of European Leagues is raising its voice and the leagues are cohesive more than ever in the defense and protection of domestic football,” said Alberto Colombo, the deputy general secretary of the European league body, in an interview.