European parliamentarian David Casa has travelled to Greece to visit former Pilatus Bank employee Maria Efimova in prison. 

In a statement issued through the EPP grouping he forms part of, Mr Casa said that he was in Athens to "make sure Maria knows that she is not alone".

Mr Casa praised Ms Efimova for her courage in speaking out, and said that whistleblowers with incriminating evidence about Pilatus Bank and its clients had been made the victims of "cruel, vicious campaigns to discredit and villify them". 

Ms Efimova has alleged, in claims first published by murdered journalist Daphne Caruana Galizia, that secret Panama company Egrant belongs to the wife of Prime Minister Joseph Muscat. 

The former Pilatus Bank employee subsequently fled Malta for Greece, saying she feared for her own safety.  

READ: Efimova could be deported back to Malta 

She is facing fraud charges in Malta following a criminal complaint filed by her former employers.

After months under the radar, Ms Efimova subsequently turned herself in to Greek police earlier this month.    

"It is not Maria that should be behind bars," Mr Casa said from Athens. "Maria asked me to express her immense gratitude for the support she has received. The actions taken by Maltese civil society are having an important impact."

Mr Casa, who is expected to meet with Greek officials and journalists later on Wednesday, told Ms Efimova that she could count on support in Brussels. 

"The European Parliament is behind her. And she will find us with her every step of the way."