This follows a temporary order made last week by a court in northern Nigeria preventing Facebook and Twitter being used to discuss the issue.
The ban was initially sought by a pro-Sharia group which said internet sites would be used to mock Islamic law.
The Sharia code runs alongside secular law in 12 of Nigeria's 36 states.
In 2000, Malam Buba Bello Jangebe was the first person in Nigeria to have an amputation carried out under Islamic law after being found guilty of stealing a cow.
The Civil Rights Congress of Nigeria started a Twitter feed, blog and Facebook debate about it so "Nigerians could air their opinions on Sharia law as a whole". But the Association of Muslim Brotherhood of Nigeria, a pro-Sharia group based in the northern city of Kaduna, argued that the forums would mock the Sharia system. The court agreed and issued a temporary ban on the internet discussions last week. Tuesday's ruling makes the ban permanent. (BBC)