FREETOWN (AFP) - Two doctors have died on the same day after contracting Ebola in Sierra Leone, the government said on Saturday, bringing to nine the number of medics killed by the virus.

They are among hundreds of healthcare workers to die treating patients infected in the deadly outbreak, which appears to be stabilising in Guinea and Liberia but is still spreading at an alarming rate in Sierra Leone.

"We lost two doctors in one day," health ministry spokesman Jonathan Abass Kamara told AFP, adding that Friday's deaths had come as "a great shock to the ministry".

"These were eminent professionals who were greatly involved in the fight against Ebola and their services will be greatly missed," Kamara said.

It was not immediately clear how either had contracted the disease, or if they were involved directly in the treatment of Ebola patients.

Thomas Rogers, a surgeon at the Connaught Hospital, the main referral unit in the capital Freetown, was being treated at the British-run Kerry Town Ebola treatment centre a short drive from the city.

He was said to be responding well to treatment when his condition deteriorated dramatically on Friday.

Dauda Koroma died at the Hastings Treatment Centre, also close to the capital, which is run entirely by local medics.

They were the 10th and 11th doctors to contract Ebola since the outbreak spread to Sierra Leone from Guinea in May, and just two have survived.

Sierra Leone has recorded around 1,600 Ebola deaths this year and has registered an worrying recent surge in cases in its western area, including the capital.

The virus is spread through contact with bodily fluids, meaning healthcare workers are particularly at risk.

More than 100 have lost their lives in Sierra Leone, which is still rebuilding from a devastating civil war in the 1990s.

The outbreak has left more than 6,000 dead worldwide since December last year, nearly all in Sierra Leone and neighbouring Guinea and Liberia.

Sierra Leone confirmed last week it was some way short of a key target to reduce the spread of Ebola by isolating almost three-quarters of patients in treatment beds.

The World Health Organisation set a 60-day goal on Oct 1 to isolate 70 per cent of Ebola patients in Liberia, Guinea and Sierra Leone and ensure safe burials for 70 per cent of bodies, which are highly infectious.

But in Sierra Leone, only 60 per cent of patients were in isolation by Dec 1, said Palo Conteh, head of the government's National Ebola Response Centre, on Friday.