"Ripping down these ads smacks of censorship and silences the voices of 700 000 people who care deeply about saving South Africa's lions," Avaaz executive director, Ricken Patel said in a statement.
"We are confident that the court will act to protect free expression and ensure this important debate about the future of South Africa's lions continues."
The posters, depicting President Jacob Zuma overseeing a lioness about to be executed with a handgun, were hung from the pillars of the airport's international arrival hall, in Kempton Park.
In August, the Airports Company SA (Acsa) told Primedia, who put the posters up on behalf of Avaaz.org, to remove the posters.
The posters, which were digitally altered to have Zuma's face on it, read: "President Zuma can save her [the lioness's] life".
The posters were part of a campaign to prevent the canned hunting of lions, as well as the sale of their organs to the Far East.
In the statement, Avaaz said that the adverts were removed because Acsa was concerned that the inclusion of Zuma, in the advertisements, would cause a "public relations nightmare".
Avaaz's Sam Barratt said it appears that the decision was politically-motivated that goes against freedom of speech and expression.
More details regarding the legal procedures would be available in the week to come, Barratt added. – Sapa