Key evidence allegedly showing two former nurses discussing killing Israeli patients will face a legal challenge, threatening their prosecution.

Sarah Abu Lebdeh and Ahmad Rashad Nadir sparked outrage after a video posted on social media by Israeli personality Max Veifer showed them saying they would refuse to treat Israelis and would kill them instead.

The pair faced court for the first time on Wednesday, when Abu Lebdeh arrived surrounded by half a dozen black-clad supporters to keep reporters away. Nadir arrived shortly after.

Neither spoke during the brief appearance in court before a magistrate adjourned both cases until May, but Nadir’s lawyer later told reporters he planned to apply to have the key video tossed out of the evidence brief.

“The video ... was recorded without his knowledge,” Zemarai Khatiz said outside Sydney’s Downing Centre Local Court. “We will apply to have it excluded.”

If the application is successful, it would leave prosecutors with little other evidence to rely on in their cases against the nurses.