Vietnam's health ministry on Sunday reported a microcephaly case that it says is likely to be the country's first linked to the mosquito-borne Zika virus.

The case, a four-month old baby whose mother was diagnosed with Zika when she was pregnant, was found in the central province of Dak Lak.

"This is a microcephaly case with a high probability of being related to the Zika virus and also the first such case in Vietnam," the General Department of Preventive Medicine, a department of the nation's health ministry, said in a statement posted on its official website.

Vietnam so far has reported a total nine cases of Zika infection, with more cases expected to be confirmed in the next few days, the department's director Tran Dac Phu told Reuters on Sunday.

If the microcephaly case is confirmed to be linked to Zika, Vietnam would become the second Southeast Asian country after Thailand to report such a case.

Vietnam earlier this month raised the threat level for Zika and stepped up monitoring of pregnant women in the country after detecting more cases and amid growing outbreaks in the region.

Zika infections in pregnant women have been shown to cause microcephaly - a severe birth defect in which the head and brain are undersized - as well as other brain abnormalities.

The connection between Zika and microcephaly first came to light in Brazil, which has confirmed more than 1,800 cases of microcephaly.