A Sydney grandmother has been sentenced to death by hanging in Malaysia on drug smuggling charges.

Three judges in Kuala Lumpur unanimously found the 54-year-old, Maria Elvira Pinto Exposto, guilty, but said she had a right of further appeal on her methamphetamine charges.

Exposto claims that she was the victim of a set-up after she was found with the drugs in her bag after arriving on a flight from China in 2014.