Nouakchott - Showing repentance will no longer prevent the death penalty from being applied for blasphemy and apostasy, Mauritania said on Friday, as the conservative Muslim nation hardens up its religious laws.

The decision follows the release on November 9 of a blogger previously condemned to death for criticising religious justification for discrimination in Mauritanian society.

A new bill will "harden up expected sentences for blasphemers," the government of the west African nation said in a statement released by the official AMI news agency.

"Every Muslim, man or woman, who mocks or insults Mohammed (peace be upon him), his angels, books... is liable to face the death penalty, without being asked to repent. They will incur the death penalty even if they repent," Justice Minister Brahim Ould Daddah said, according to the statement.

The decision to free blogger Cheikh Ould Mohamed Ould Mkheitir for time served after his sentence for blasphemy was downgraded from death to two years in jail caused clashes and outrage in Mauritania last week.

A Muslim in his thirties, Mkheitir was sentenced in December 2014 over a blog which questioned decisions taken by the Prophet Mohammed and his companions during holy wars in the seventh century.

He also attacked the mistreatment of Mauritania's black population, blasting "an iniquitous social order" with an underclass that was "marginalised and discriminated against from birth."

Prosecutors have appealed the decision to release the blogger and are calling once more for the death penalty to be handed down.

Mauritania has not carried out the death penalty since 1987.

Justice Minister Ould Daddah said times had changed since the original law was written in 1983, and "consequentially the law has to move on," AMI reported.