Protester chained inside a mock prison cell representing Palestinian prisoners in Israeli jails.

A protester is chained inside a mock prison cell representing Palestinian prisoners in Israeli jails. Photo: Adem Altan

THE number of Palestinian prisoners on hunger strike in Israeli jails has grown to at least 2800, human rights groups say, while two of the inmates hovered close to death as they entered their 69th day without food.

Israel's practice of jailing people without charge - known as administrative detention - is the main issue driving the hunger strikers, whose images are seen on posters throughout the West Bank and Gaza as the protests backing the prisoners continue to grow.

About 320 Palestinians are being held in administrative detention in Israeli prisons - 24 of them are members of the Palestinian Legislative Council.

They were not informed of the accusations or evidence against them, there was no trial and they had no opportunity to defend themselves, the prisoners' rights group Addameer said.

Their term of imprisonment is determined by an Israeli military judge, and it can be extended indefinitely.

Tha'er Halahleh, 33, and Bilal Diab, 27, the two prisoners who have been on a hunger strike for 69 days, had their appeals against their imprisonment without charge rejected by a military court last month.

Their cases are now before Israel's High Court, which was expected to make a ruling overnight. Halahleh has been held without charge for 22 months, Diab for nine months.

Israel has consistently defended its use of administrative detention, saying it is a vital security measure that prevents terrorist attacks and that disclosing evidence could put security operations and informers at risk.

The Israeli Prison Service disputes the number of prisoners on hunger strike and rejects the claims that lawyers are not being given access to the prisons.

Spokeswoman Sivan Weizman says 1600 prisoners were refusing food. ''We have a committee that is going from prison to prison to discuss the prisoners' concerns. We will tell them soon about our decision,'' she said.

The UN special rapporteur on human rights in the Palestinian territories, Richard Falk, said Israel must fulfil its international human rights obligations to all Palestinian prisoners.

Mr Falk noted that since the 1967 war, an estimated 750,000 Palestinians, including 23,000 women and 25,000 children, had been held in Israeli jails - this was 20 per cent of the total Palestinian population and 40 per cent of the total male Palestinian population.