SANTIAGO, Nov 12 (Reuters) - Chilean lawmakers on Wednesday demanded an investigation of a mushrooming AIDS scandal after the government said the public health system had failed to notify at least 320 people that they were infected with HIV virus.

Some lawmakers called on the government to declare a health emergency.

Chile's health minister resigned last month after it emerged that a hospital in far northern Chile failed to notify dozens of patients that they had tested positive for HIV.

New Health Minister Alvaro Erazo told lawmakers on Tuesday at least 320 people across the country had not been informed they were carrying the virus. He has promised to give a Congress health commission concrete figures on Thursday.

"There must be a much deeper investigation into the health system," Juan Lobos, president of the health commission of the Lower House of Congress, told local media. "All health service directors should hand their resignations to Minister Erazo."

Government Minister Francisco Vidal said President Michelle Bachelet's administration was dealing with a serious problem but dismissed suggestions of a potential epidemic, saying Erazo was working to ensure the debacle would not be repeated.

Senator Guido Girardi, from the ruling center-left coalition, said he believed the private health sector also failed to inform hundreds of patients that they were infected with HIV.

"There are an important number of cases in the private sector which I ask be investigated," Girardi told reporters. "We could be talking about around 600 cases in the private sector, which added to the 320 in the public health system, would mean around 1,000 patients nationally."

He gave no details on how he arrived at his estimate for cases in the private sector.

AIDS activists were outraged.

"Failing to adequately inform patients of the positive results of their HIV tests is not just a problem of management or human error but clearly goes against the law," groups Vivo Positivo and Asosida said in a joint statement.

"It is a flagrant violation of human rights and the right to life," they said. "It is the worst sanitary crisis the country has faced in recent years."

Before she quit when the scandal broke last month, former health minister Maria Soledad Barria removed the head of medicine, the supervising nurse and the head of the blood bank at a hospital in Iquique in northern Chile pending an investigation into possible negligence.

Bachelet's center-left coalition government has been battered by protests and scandals in recent months, helping boost its rightist rivals ahead of what is seen as the toughest presidential race since the return to democracy two decades ago.

Bachelet, who trained as a doctor and was a former health minister, is an AIDS expert. (Reporting by Reuters Television and Monica Vargas; Writing by Simon Gardner; Editing by Bill Trott)

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