The Southern Health Board has said that infant mortality in its region - which appears higher than most other areas in the State - is caused by low birth-weight, congenital abnormalities and infant death syndrome.
The Green Party in Cork has called for a comprehensive study to find out why this is happening. However, the health board says that infant mortality is the result of complex and multiple factors.
"It is recognised internationally that one of the major determinants of infant mortality is social and economic deprivation."
The figures for infant mortality for the SHB areas of Counties Cork and Kerry had been examined going back to 1987, a board statement said.
"It is apparent that the Cork city area tends to have higher mortality rates than Co Cork and Kerry. However, it should be noted that in 1997 the infant mortality rate for Cork city had dropped dramatically to 4.6 per 1,000, which is below the national average of 6.2 per 1,000.
"Cork city is known to have higher levels of low birth-weight babies - a risk factor in itself for infant mortality. It is recognised that areas in Cork city also have high levels of social deprivation."
The statement added: "While well-developed health services are important, of even greater significance is the need to address the associated social and economic factors such as poverty, nutrition and smoking - all of which contribute to poorer health status and consequently higher infant mortality."
Mr Dan Boyle, a city councillor, said the infant mortality rate should be investigated urgently.