Reports are emerging that hunger strikers in Rangoon’s Insein prison have been have denied drinking water by authorities as they attempt to break the protest, now in its sixth day.

Around 20 more political prisoners are also believed to have joined the 15 already on hunger strike. They are protesting a decision not to overturn a ruling that bars the majority of prisoners from the right to have their sentences reduced.

Eight of them have been placed in solitary confinement, while visiting family members have been turned away and parcels destined for the strikers confiscated, said Aung Zaw Htun of the Assistance Network for Families of Political Prisoners.

“Some of the prisoners serving long-term sentences were already in poor health prior to the hunger strike,” he said. “The prison authorities are yet to give in to any of their demands and banned them from receiving family visits.”

He said the denial of  clean water and parcels, which may contain medicine, triggered “huge concern” over their health. “We are now collecting signatures for a petition calling for an immediate [response] to the matter.”

Until 1997, Burmese penal law entitled all prisoners, except for those on death row or serving life sentences, to small remissions of their sentences, often only a few days per year. The strikers are complaining that the revocation was unfair and should be overturned.

Ko Ko Gyi, a former political prisoner who was released in an amnesty this month, said that even Burma’s president had called for the law to be reintroduced.

The last hunger strike in Insein prison, in May this year, was dealt with harshly by prison officials. Nearly 30 inmates began refusing food a day after Burmese authorities announced a highly criticised amnesty that saw nearly 15,000 people released from jail early, but only 55 of whom were political prisoners.

Ten days into the strike, at least seven inmates were placed in solitary confinement and kept there for several days until authorities acceded to a number demands focused broadly on prisoners’ rights.