Couples are being advised to take an HIV test before they marry, the Anglican Church in Nigeria says.
Nigeria is a deeply religious country
The church says the move is to help parishioners make "informed choices" when choosing marriage partners.
The BBC News website learnt that many Christian churches in Nigeria impose similar tests on their members as a condition for marriage.
The policy is being implemented in all Anglican dioceses across Nigeria, the church's spokesman said.
"The aim is to help intending couples to make informed decisions because we don't want anyone to be kept in the dark about their partner," spokesman for the church Rev Akintunde Popoola told the BBC News website.
He said the church will not stop people from getting married if they test positive to HIV, the virus that causes Aids.
"The whole point is for couples to know their HIV status before getting married," he said.
"If they find out their status and still want to go ahead, we cannot object. Instead, we offer them care and support."
But the authorities are already challenging the new policy by the church, saying it is unacceptable.
"We cannot accept what the church is proposing. Every Nigerian must be allowed to decide on their own whether they want to be tested or not," Prof Tunde Oshotimehin, who heads Nigeria's state HIV control agency, told the BBC.
"HIV testing and counselling must be voluntary. What the church is trying to do will encourage denial."
The Catholic Church in Nigeria says it is not imposing such a policy on its members because it wants HIV testing to be voluntary and personal.
"We know that some people do it, but we are not making it church policy," spokesman of the Catholic Archdiocese of Abuja Rev Fr Ralph Madu told the BBC News website.
Recently, a church-owned college - Covenant University, Nigeria - announced that its graduates should take HIV and pregnancy tests as conditions for graduation.
But the university suspended the policy after widespread condemnation and criticisms from government agencies and rights groups.
Nigeria is a deeply religious country with her 140 million people almost evenly divided between Christians and Muslims.
According to Nigeria's National Agency for the Control of AIDS (Naca), some 4.4% of Nigerians live with HIV.