The country's congress is holding a closed-door session on Wednesday to discuss whether the mininum age should be lowered from 15 years old to nine years old.
World Vision Philippines said the move would constitute "a clear violation of the international human rights treaty bodies such as the United Nations Convention on the Rights of a Child (UNCRC), where the Philippines is a member state."
Lowering the age of criminal responsibility will encourage syndicates to use younger children. #ChildrenNotCriminals https://t.co/m9TgGtR5iU pic.twitter.com/qYNQq8x3q3
— World Vision PH (@WorldVisionPH) January 25, 2017
Legislation has been prepared by the government of controversial president Rodrigo Duterte to lower the age of criminal responsibility, in response to concern drug gangs are using child couriers who are too young to be sent to prison.
Last month Duterte said the Juvenile Justice Welfare Act - which exempts those under the age of 16 from criminal liability - had produced a "generation of criminals".
World Vision Philippines has called on the state to instead address the "root causes that force children to commit crimes to survive".
The organisation also voiced concerns children will end up in prison because of a lack of youth rehabilitation facilities in the Philippines.
In a statement, it said: "Children should not fully bear the consequences of their committed crimes, which are usually or possibly influenced and exploited by the parents or abusive adults."