Authorities in Indonesia's Aceh province are pressing ahead with a proposed law that would ban female passengers from straddling motorbikes despite reported opposition from the central government.

Aceh introduced a version of Shariah, or Islamic law, in 2009, following through on a deal struck in 2005 to end a long-running separatist war there. The Aceh laws regulate women's dress and public morality, and allow for public caning.

On Monday, authorities in northern Aceh distributed a notice to government offices informing residents of the proposed law, which would apply to adolescent girls and women.

Suaidi Yahya, mayor of the Aceh city of Lhokseumawe, said a ban was needed because the "curves of a woman's body" are more visible when straddling a motorbike as opposed to sitting sideways with legs dangling.