A New Zealand nurse who was kidnapped by Isil in Syria six years ago may still be alive, her employer the Red Cross has said, breaking their silence in an attempt to find her.

Louisa Akavi, 62, was abducted along with two Syrian colleagues in October 2013 while delivering International Committee for the Red Cross (ICRC) aid in rebel-held Idlib in the northwest of the country.

The ICRC had requested that Ms Akavi’s case was not made public for fear that it may endanger her.

“We are speaking out today to recognise Louisa’s, Alaa’s and Nabil’s hardship and suffering and to call for any information that could provide more leads into their whereabouts and wellbeing,” said Dominik Stillhart, director of operations for the ICRC, revealing she is the longest-held hostage in the 156-year history.

The organisation had been in intermittent contact with the Islamic State of Iraq and the Levant (Isil) jihadists holding her, who were demanding millions of dollars for her release. But communication dried up by late 2014.