The bodies that represent broadcasters in Europe and around the world have called for the immediate release of the BBC correspondent in Gaza.
Alan Johnston disappeared more than four weeks ago on his way home from work. It is feared he was abducted.
The broadcasting unions said the media gave a voice to people in conflict zones, and journalists should never become victims of their own profession.
The Palestinian government said it is "deeply sorry" he is still being held.
On Tuesday, Palestinian Information Minister Mustafa Barghouti said the government was making every effort it could to secure Mr Johnston's release.
"We in the government are deeply sorry and ashamed that this kidnapping is ongoing, especially since he is a friend of our people and has done a lot for our cause.
"His kidnapping is detrimental to our nation and our national cause," Mr Barghouti said.
Johnston was taken hostage by masked gunmen as he returned to his apartment in Gaza City on March 12.
Kidnappers have abducted dozens of foreigners in Gaza, but none have been held so long as Johnston.
Johnston joined the BBC World Service in 1991 and has spent eight of the last 16 years as a correspondent, including periods in Uzbekistan and Afghanistan.
He has lived and worked in Gaza for three years and was the only Western reporter permanently based in the often violent and lawless territory.
His posting in Gaza was to end at the end of March