A Palestinian journalist imprisoned by Israel without trial is in poor health after nearly 50 days on hunger strike, his wife said on Monday.

"He is vomiting blood and has lost 25 kilogrammes (55 pounds)," Mohammed al-Qiq's wife, Fayha Shalash, told AFP.

She said that if he loses consciousness she believes his doctors will feed him intravenously.

A controversial Israeli law passed in July allows the force-feeding of prisoners in certain circumstances, though it has not yet been invoked.

Qiq, a 33-year-old reporter for Saudi TV channel Al Majd, was arrested on November 21 at his home in the West Bank city of Ramallah and in mid-December placed under administrative detention, which allows imprisonment without trial for six-month periods renewable indefinitely.

He began a hunger strike on November 25, alleging torture by his captors and is currently in the hospital wing of Ramle prison, in central Israel.

He was jailed in 2008 for 16 months for student activism which Israel says was linked to Islamist militant group Hamas.

Palestinians have regularly gone on hunger strike to protest administrative detentions.