An Australian academic being held in an Iranian prison has reportedly begun a hunger strike, along with another academic.

Melbourne University lecturer Kylie Moore-Gilbert has been held in the notorious Evin Prison in Tehran since October 2018.

She was accused of spying and has been convicted and sentenced to 10 years. A recent appeal failed.

AP

In a letter dated Christmas Eve and published by supporters of Dr Gilbert-Moore and French-Iranian researcher Fariba Adelkhah, the women say they have begun refusing food and water.

READ MORE Third Australian detained in Iran identified as Melbourne Islamic studies lecturer

Foreign Minister Marise Payne has told SBS News the reports are troubling, maintaining the Australian government is doing all it can to assist Dr Gilbert-Moore.

"This is a matter of deep concern to the Government and to me personally as Foreign Minister," she said.

"The Government continues to insist that Dr Moore-Gilbert be treated fairly, humanely and in accordance with international norms. I have communicated with my Iranian counterpart, Foreign Minister Zarif, many times about this case, including through face-to-face meetings."

Australian Government says situation 'complex'

The government has previously described Dr Moore-Gilbert's situation as complex, and Senator Payne has said Australia did not accept the spying charges against her.

"She's been receiving consular assistance and had a visit recently," Prime Minister Scott Morrison said on Tuesday.

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"But I can assure you, and I know the extent that Kylie knows and we're doing everything that we can do bring her home."

Mr Morrison said the government remains concerned for Dr Moore-Gilbert's welfare.

West Australian couple Jolie King and Mark Firkin were arrested in Iran in August but released in October after talks with the Foreign Affairs Department.

With wires...