Iranians vote in presidential election tipped in favour of hard-liner

Ebrahim Raisi casts his vote at a polling station in Tehran (Ebrahim Noroozi/AP)

Iranians have begun voting in a presidential election tipped in favour of a hard-line protege of Supreme Leader Ayatollah Ali Khamenei.

State-linked opinion polls put judiciary chief Ebrahim Raisi as the dominant front-runner in a field of just four candidates.