Foreign Affairs Secretary Blas Ople had earlier inquired about the possibility of releasing them as a goodwill gesture to Chinese Prime Minister Li Peng, who is scheduled to vist the country next week.
"If they don’t plead guilty, then we’ll continue with the prosecution," Perez told reporters in an interview.
However, a senior foreign affairs official who spoke on the condition of anonymity said the poachers’ release was "not possible" because criminal cases against them have been already filed in a Puerto Princesa City court in Palawan.
Earlier, Senators Francis Pangilinan, Noli de Castro and Manuel Villar sent Perez three Senate resolutions calling for the prosecution of the poachers. The resolutions are non-binding.
If the poachers plead guilty, Perez said the time they have already spent in jail would be credited to their sentence. The poachers were arrested early this year near Tubbataha Reef, a popular dive spot in Palawan.
Accused of illegal fishing and illegal possession of endangered species, the poachers face a maximum penalty of six months imprisonment and a fine of $100,000.
Turtles and giant clams, both under the country’s endangered species list, were found on their boats.
"We would also insist on confiscating the six vessels used by them because they will be using the same vessels again if they come back," Perez said.
Meanwhile, mayors of various coastal municipalities yesterday issued a statement opposing the poachers’ release, saying it would "send wrong signals to foreign poachers encroaching on Philippine waters."
"The propriety of releasing these illegal fishers is wrong. This will encourage other foreign fishermen to encroach on Philippine waters using illegal fishing methods such as dynamite blasting and cyanide poisoning to catch the endangered marine species," said Mayor Pacifico Mayor, of Ferrol, Romblon.