CONAKRY (Reuters) - Guinea's production of alumina, a derivative of bauxite used to produce aluminium, rose 38.6 percent in the first half of the year, compared with the same period a year ago, according to a government report seen on Thursday.

Alumina production for the year hit 315,600 tonnes by June, according to the Ministry of Finance report.

Bauxite production rose 6 percent to 8,266,900 tonnes in the same period, exceeding its target by 1 percent.

Emmanuel Sassouadouno, a senior official at the Ministry of Finance, said the rise in production was due to the country's return to stability and investor confidence.

"We noticed the same trend in the diamond sector and relatively in the bauxite sector also," Sassouadouno said.

Guinea last year elected Alpha Conde as its president, ending two turbulent years of military rule.

The report said diamond production also jumped 41 percent to 202,900 carats, while gold production fell 15.2 percent to 372,600 ounces in the period.

Sassouadouno however said the country would remain cautious about forecasts for the months ahead due to the sharply deteriorating global economic climate.

RUSAL's 640,000-tonne-a-year capacity Friguia alumina refinery is the west African nation's only refinery.