Lindsay Sandiford, 56, from Cheltenham, Gloucestershire, was convicted last week of taking 10.6lb of the drug into the country.
She received the sentence despite prosecutors asking for a 15-year jail term.
It was announced yesterday the British Government is to be challenged over its failure to fund legal representation for Sandiford, who it is thought cannot afford legal representation for the appeal.
Law firm Leigh Day, working with the charity Reprieve, said Sandiford, originally from Redcar, Teesside, had not been properly represented since her arrest at Bali airport in May last year. It is seeking a judicial review of the Government's decision not to pay the £2500 legal expenses for Sandiford.
A hearing at the High Court in London will be held before Thursday.
The Foreign and Commonwealth Office said the Government does not fund legal representation for British nationals abroad, but Sandiford's case was being raised through diplomatic channels.