Hong Kong warned expectant mothers from mainland China against rushing to emergency wards without prior bookings, saying they were putting their babies' lives at risk.
The Hospital Authority (HA) said there were 116 cases of "non-local mothers" going to emergency departments (AEDs) in the southern city last month, of which only 39 had bookings for maternity services.
The warning comes as the former British colony of seven million people struggles to cope with demand for maternity services from mainland women, tens of thousands of whom come to the southern city every year to give birth.
The government has imposed quotes and toughened border controls amid protests from local women about shortages of beds and rising costs of maternity care.
"The HA reiterated and appealed to the non-local expectant mothers that it is a high-risk behaviour to rush to AEDs at the last minute to deliver, posing risk to both the mother and the baby," it said in a statement.
Emergency wards lack standard staffing and facilities as well as antenatal records, and were not equipped to deal with complicated cases, it said.
"Even in public hospitals with obstetric services, their service capacity will be filled by previously booked cases, leaving little room for non-booked cases," it added.
"The HA appeals to non-local expectant mothers to make proper and appropriate delivery arrangements for the well-being of both themselves and their babies."
Hong Kong's next leader, chief executive-elect Leung Chun-ying, has said he will ban pregnant mainlanders whose husbands are not from Hong Kong from giving birth in local hospitals next year.
He has also said the children of such women will not be guaranteed residency rights as they have been in the past.