Uefa boss Michel Platini has pledged to help Cardiff if they win the FA Cup but are refused entry to the Uefa Cup.
Cardiff played superbly to beat Middlesbrough in the FA Cup
The Football Association says Cardiff will not be one of England's Uefa Cup representatives as the club comes under the jurisdiction of the FA of Wales.
"If England don't do anything we will," Uefa president Platini told BBC Sport.
In the most open FA Cup for years, Cardiff play Barnsley in the semis, with the winners due to meet either Portsmouth or West Brom in the final.
"We have to respect the result on the field," added Platini.
Under current FA rules, Cardiff is considered a Welsh club with full membership of the Football Association of Wales (FAW), but only associate membership of the FA.
"We spoke with the FAW," added Platini.
"I think it is not normal that if they win then they're out. That's not natural and not so good."
Winners of the FA Cup are currently handed a Uefa Cup spot by the FA, who run the competition as a reward for winning it.
Cardiff chairman Peter Ridsdale has hinted the club would challenge the English FA's current rules and regulations.
Cardiff could cite several examples to support their case including:
- Derry City - Based in Northern Ireland but since 1985 have been playing in the Republic of Ireland's competitions and are regarded as a Republic of Ireland club. When they qualify for Europe, they play as a Republic of Ireland team.
- AS Monaco - Based in Monaco, where they are the only side, but play in the French League.
- Berwick Rangers - Based in England but play in the Scottish League and would be accepted as a Scottish club if they qualified for Europe.
When the FAW formed the League of Wales in 1992, Cardiff, Swansea City and Wrexham all decided not to join it choosing to remain playing in the English Football League.
As a result, Uefa decided the clubs would no longer be allowed to compete in the Welsh FA Cup and therefore would not be allowed to qualify for Europe that way.
The FAW agreed with that decision and Uefa take the view that because they play in English competitions, they are English clubs.