A crisis meeting between Merseytravel and senior officials and councillors from Liverpool and Knowsley councils has now been called for later this week.
The Merseytram committee resolution finally expressed its "extreme concern at the actions of the Liberal Democrat controlled city council, which jeopardise another key project from the Magnificent Seven projects at the heart of the European Capital of Culture Programme in 2008."
Cllr Peter Millea, executive member for regeneration, said: "It is not correct to say that the council is jeopardising the building of lines one and two, because the funding for line two isn't even in place yet.
"And the route we are proposing would take it into Knowsley via Halewood. This could be further extended into the borough when plans for line three are worked up.
"We are simply asking Merseytravel to look again at line two to take into account the expansion of the airport and regeneration of south Liverpool."