Deputy attorney general Omar Makungu said if enacted the new law would also ban same sex marriages.
Under current laws, homosexuality is already illegal, but Mr Makungu
says they want to stop the practice becoming an accepted part of Zanzibari culture.
Correspondents say the number of homosexuals and lesbians is on the rise in the Indian Ocean Island.
"We have heard that same sex marriages have taken place here and we want to guard against this trend," Mr Makungu
told the BBC Swahili service. He
said they have also proposed a maximum life imprisonment sentence for anyone found guilty of sodomy.