They told the News Agency of Nigeria (NAN) that cremation was against the Christian, Islamic and traditional beliefs.
Fashola had said that the law would allow the residents to burn their loved ones, if they so wish.
The governor said that the law was enacted to provide more choices in a growing global state and accommodate the different beliefs of residents.
The bill was passed by the Lagos State House of Assembly on Dec. 28, 2012.
The law empowers medical practitioners, with the government’s approval, to cremate abandoned and unclaimed corpses after a reasonable period of time had been given as notice.
Monsignor Gabriel Osu, the Director, Social Communications, Catholic Archdiocese of Lagos, said that cremation was an abuse against the human body, which he described as “the temple of God“.
Osu said that the human body should be treated with dignity.
“Cremation is not our culture, neither is it our tradition, neither is it our fashion. I am sure that if you ask Muslims and Christians, majority will definitely say no.
“I don’t think that cremation is in the interest of the people. It is anti-peoples.
“In Christianity, in Islam, in our custom, even our tradition, we treat the dead with respect; we bury the dead well.
“The church’s stand on it is very clear. Once you still believe in immortality, we believe in life after death, you believe in resurrection and if the body is the temple of the Holy Spirit, it must be well-respected.
“But, it is the poor really who is still being affected because he died without dignity; he died in pains, he died being neglected, now again, you say ‘burn him’. That is the problem.
“You know the bottom line; our attitude to the dead is zero; so anything that comes our way, we take it.”
Imam Shuaibu Abdulahi, the Executive Director of Zakat and Fadaqat Islamic Foundation, told NAN that Islam forbade the burning of human bodies.
Abdulahi said that the foundation had written the lawmakers stating the position of the Islamic group on cremation.
He said the letter did not yield the desired result.
According to him, at the public hearing on the matter, majority of Nigerians did not agree to cremation.
He said it was sad that government refused to listen to the voice of the majority even in a democratic setting.
“Cremation is against the injunction of the Qur’an, also against the principles of Christianity.
“Be that as it may, our position has not changed which is, the Almighty God who created man, from the Islamic point of view, specifically forbids cremating human beings, whether they are believers or they are unbelievers; this is the position of Islam.
“However, government has gone ahead to sign the law which is an indication that government is not listening to the popular voice of the people, because democracy is about doing the bidding of the majority.”
Also, Mr Lekan Ajirotutu, spokesperson of the Association of African Traditional Religion of Nigeria (AATREN), said that cremation was a taboo.
Ajirotutu said that such act could cause bad omen in the land, a situation, which, he said, would “require appeasing the gods“.
“Traditionally, culturally in African tradition, it is wrong. It has a negative effect on the land too.
“A land where they cremate, where they burn humans, it has a traditional taboo because we believe it is not a decent way to bury human beings.
“And when it happens accidentally, we have to appease the gods so that we don’t see such again.
“It is like when people are carried by river or somebody hangs himself, we have to appease gods so that such a thing will not recur in that community.
“In a situation whereby you voluntarily roasted a human, then, it is a taboo on the land. So, in traditional religion and cultural belief, it is wrong.”