One of the close contacts with the sixth confirmed case of human infection of H7N9 in Hong Kong was tested positive for influenza A (H1) virus, said Hong Kong health authorities.

The Center for Health Protection under the Department of Health of Hong Kong said on Wednesday that an 18-month-old girl was confirmed with infection of the virus.

She received treatment in Queen Elizabeth Hospital on March 1 and was discharged on Monday, according to Xinhua News Agency.

Her sample was later confirmed positive for H7N9.

The center didn't disclose whether the girl was exposed to poultry.

Of her 13 close contacts, two showed related symptoms, one of whom was tested positive for influenza A, said the center.

"In view of human cases of avian influenza A (H7N9) confirmed locally and multiple cases reported by the mainland, further cases are expected in affected and possibly neighboring areas," said a spokesman for the Department of Health. "Those planning to travel outside Hong Kong should maintain good personal, environmental and food hygiene at all times."