Health authorities said on Wednesday they are following up on allegations that two Hong Kong laboratories have been performing fetal gender tests with smuggled blood samples from pregnant women on the mainland.

The Department of Health (DH) said in a statement that it launched a probe after receiving media enquiries about online promotions of these services by 'NovaGene Diagnostic Laboratory' and 'Zentrogene Bioscience Laboratory'.

Under the Allied Health Professions Ordinance, medical laboratory technologists are not allowed to perform diagnostic tests without a referral from a registered medical practitioner or other specified healthcare professional.

Those who wish to import any blood or blood component suspected of containing an infectious agent must also seek prior approval from the Department of Health.

Authorities said they have referred the case to the Medical Laboratory Technologists Board for follow-up action, adding that the relevant mainland authorities have also been informed.

In addition, the department said the two laboratories in question falsely claimed themselves as "medical laboratories accredited by the DH".

The department stressed it has never accredited any medical laboratories.

Separately, officials found that two medical centres – 'Nova Medical' and 'Hong Kong BOYA Medical Center' -- have never applied for clinic licenses or registered under the Medical Clinics Ordinance.

"Despite this, 'Hong Kong BOYA Medical Center' claimed to be a 'Hong Kong registered medical clinic'. The DH has referred these cases to the Hong Kong Customs and Excise Department for follow-up and requested the removal of all misleading statements," the government statement read.

The department said it found suspected misleading promotions for other medical services on the two centres' websites, and that it has issued warnings and ordered the removal of the misleading content.