Schapelle Corby's lawyer says the Australian could be released from prison in Indonesia next month after her sentence was reduced.

Corby was convicted in 2005 of smuggling marijuana into Bali and sentenced to 20 years' in prison, including time spent awaiting trial. In May, Indonesia's president reduced her sentence by five years. Friday's six-month reduction means she has now served two thirds of her sentence and is eligible for parole.

Lawyer Iskandar Nawing says they are arranging necessary guarantees from the Australian Consulate and Corby's family to apply for parole next month. He says he expects Corby to be released in late September.

The 34-year-old Corby was among 58,595 prisoners across Indonesia whose jail terms have been reduced to mark Independence Day. More than 2,200 were freed.

Her case drew intense interest in Australia, where many people believe she is innocent.