Tamil prisoners who are in a continuous hunger strike would not stop their action as the government had failed to fulfil a pledge to release them, Wigneswaran said in a letter to President Maithripala Sirisena.
The death of one of the prisoners on hunger strike would make the Tamils lose faith on the government, he said.
Some 32 of them were granted bail this week but the bail conditions imposed on their release have caused disappointment among them.
"Mr Sampanthan (TNA leader) said he trusted the President 100 per cent and assured that all of us will be released by 7 September. He is not even in the country now," said S Sulakshan, who had been in detention since 2012.
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He said tough bail conditions have been set, it would be difficult for the rest of the detained to gain bail.
Following hunger strikes in prisons all over the country last month, Sirisena had pledged to solve the issue by November 7.
Over 200 Tamil prisoners went on a five-day strike last month which they suspended following assurance from Sirisena who promised to expedite the processing of their cases. They later continued their hunger strike alleging government had failed to fulfil its pledge.
However, later the government said it has decided not to grant a common amnesty to the Tamil prisoners but will expedite bail procedures for a section of the Tamil prisoners who are charged with minor offences.
However, Justice Minister Wijeyadasa Rajapaksha on several occasions has said that there are no political prisoners held in any of Sri Lanka's prisons and some of the LTTE suspects held in the prisons currently are already serving sentences and others are awaiting court action.
He said that all these suspects have charges against them relating to bombings and killings.