Enormous billboards have been put up in an Islamic State stronghold in Libya warning women they must wear a baggy hijab that covers their entire bodies and no perfume.

The posters set out 'Sharia stipulations for hijab', which include wearing dense material, no big brand names and a robe that does not 'resemble the attire of unbelievers', The Daily Mail reports.

The billboards have been put up in Sirte in Libya, where militants have been busy instilling its brutal interpretation of radical Sharia law.

ISIS has been able to gain a foothold amid chaos in Libya, where two governments backed by rival alliances of militias are battling each other as well as extremist groups. 

It is believed the number of ISIS killers has swelled from just a few dozen in Libya last year to some 2,000.

The latest instrument of oppression is a huge billboard depicting a woman covered head to toe in a black robe, alongside the list of 'stipulations'.

The hijab must baggy and cover the whole body, and made of heavy material. It must not be made by a famous brand, resemble men's clothes or garments worn by 'female unbelievers', be decorated so it attracts attention, or be scented.

Punishments for breaking the code of conduct have also been established, ranging from 80 lashes for drinking alcohol and losing a hand for theft, to death for committing blasphemy. 

Those who commit adultery will be stoned to death if the adulterer was married and lashed 100 times and exiled if he or she was unmarried. 

Those engaged in sodomy (homosexuality) will be sentenced to death, along with those who 'spy for the unbelievers'

A document revealing the list of crime and punishments was released late last year, but ISIS is inventing increasingly sadistic methods to punish people.