Before he joined the Health Ministry, an area in which he had no training, Mr Gao had been a low-profile figure, but he quickly stepped into the spotlight in a publicity campaign to rescue Beijing's damaged image in handling the Sars outbreak.

His media debut as executive vice-minister in 2003 was at a press conference packed with journalists who were sceptical about Beijing's handling of the Sars epidemic in April that year.

However, Mr Gao's praise for former health minister Zhang Wenkang and his denial that he had been sacked over Sars backfired. Two weeks later, Mr Gao called the dismissal of Mr Zhang 'correct'.

The economist was appointed health minister in April 2005 when Vice-Premier Wu Yi formally passed the baton to him after Sars was no longer a threat.

Mr Gao's career as deputy health minister and minister was marked by his role in handling a series of public health scares such as Sars, Aids, bird flu and swine streptococcus.

Analysts believed Mr Gao was appointed to head the Ministry of Health because the government wanted to use his financial expertise to improve the efficiency and funding of the health sector.

But Mr Gao's lack of medical training made him a controversial health minister - some said he made sensible decisions as a politician while others said his remarks and decisions upset many medical practitioners.

Mr Gao was under fire from 2005 as public grievances mounted over unaffordable health care and rampant corruption in the medical sector.

He criticised inefficiency in the medical sector and even took responsibility on the sidelines of the annual meeting of the National People's Congress in 2005, telling reporters that he should be blamed for not submitting a good health reform plan to the State Council.

But when asked the same question at the same occasion the next year, Mr Gao said medical reforms were the work of more than 10 government ministries and there were no quick cures.

That remark, true though it was, saw him come under heavy fire from an impatient public and many internet surfers posted messages saying that Mr Gao was shirking responsibility.

The incoming minister, Chen Zhu

The appointment of 54-year-old medical researcher Chen Zhu as health minister will give the top scientist the opportunity to display his diplomatic and political skills in the bureaucratic labyrinth.

There is little doubt Professor Chen's international exposure and connections - he has studied and worked in France and the United States - will help improve the mainland's communication with the global community in areas of public health co-operation such as bird flu.

It is also expected that he will be able to help improve the country's international image and boost its medical research efforts.

Overseas scientists who have worked with Professor Chen say the fluent English-speaker is friendly and open-minded.

He was director of the Chinese Human Genome Centre in Shanghai, director of the Shanghai Institute of Haematology at Ruijin Hospital, and a vice-president of the Chinese Academy of Sciences.

Professor Chen received his doctoral degree at the University of Paris VII's St Louis Hospital in 1989 and has co-operated widely with overseas scientists in research projects as a molecular biologist and an expert on leukaemia.

A source close to the Ministry of Health said one of the reasons for choosing Professor Chen was his support for traditional Chinese medicine.

But politics would have played a bigger role in his appointment.

Giving more top government posts to non-communists has become a way for the leadership of President Hu Jintao and Premier Wen Jiabao to justify one-party rule and answer calls for political reform. Beijing appointed Wan Gang , also a western-trained non-communist, as science minister in April.

'It reminds people of the first health minister, Li Dequan , who was also a non-communist,' said a mainland journalist who covers medical issues.

But whether a scientist can survive as a politician remains unclear in such uncharted waters.

Professor Chen's only administrative experience was as deputy president of the Chinese Academy of Sciences and a director of a hospital in Shanghai.

The first hot potato to land on Professor Chen's desk will probably be the draft plan for mainland healthcare reform.

One of the driving forces for the reform has been the need to assuage public grievances over inefficient and expensive health-care provision, but tension has been growing as vested interest groups have tried to hold onto their turf and government departments have bargained to secure more resources.

No matter what the new reform plan ends up looking like, it will draw criticism from some quarters, and Professor Chen will face the tremendous challenge of negotiating with different departments while addressing the demands of an impatient public.