An Israeli military court on Monday rejected appeals by two Palestinian prisoners who have been refusing food for 55 days, their lawyer and a Palestinian prisoner rights NGO said.

"We just confirmed with Bilal Diab and Thaer Halahla's families that both their appeals were rejected today," a spokeswoman for prisoner rights group Addameer told AFP.

Diab, 27, and Halahla, 34, began refusing food on February 29 in protest at being held without charge under a procedure known as administrative detention, which means they can be held for renewable periods of up to six months.

They are being held in the hospital wing of Ramle prison near Tel Aviv, with their condition described as "rapidly deteriorating."

Their lawyer, Jamil al-Khatib, said the military judge had rejected their appeals, saying the two prisoners were "responsible for their own state of health."

"Yesterday the judge held a closed meeting with the Shin Bet (internal security service) and the military advocate general, and he examined their appeals.

"He looked at the confidential files and decided that their hunger strike was their choice and does not affect the danger which they pose," he told AFP.

The prisoners had both lost 25 kilos (55 pounds) and had "entered a dangerous phase," Khatib said, indicating he would visit the pair at Ramle prison on Tuesday.

"I will also make an appeal to the (Israeli) High Court tomorrow," he said.

According to Physicians for Human Rights, Halahla has been in detention since June 2012, and Diab since August 2011. Both are allegedly associated with Islamic Jihad, but they have not been prosecuted.

The two began refusing food after their detention orders were renewed as part of a wave of protests among administrative detainees sparked by the hunger strikes of two other prisoners, Khader Adnan and Hanaa Shalabi.

Adnan went 66 days without food and only agreed to end his strike after Israel agreed not to renew his detention beyond the original order.

And Shalabi was also released after 43 days on hunger strike on condition she be exiled to Gaza for three years.

Over the past week, another 1,350 Palestinian prisoners have begun an opened-ended hunger strike in protest at the conditions of their detention, the Israel Prisons Service said on Sunday.