Guidance on a how to reduce the risk of swine flu spreading has been issued by health chiefs.
Britons should avoid taking any nonessential trips to Mexico, the Foreign Office has warned, and any travellers returning from affected regions should contact a doctor or NHS Direct if they experience illness within a week of returning.
However, the Health Protection Agency (HPA) said that travellers do not need to isolate themselves from the public if they show no signs of illness.
Medical staff are being advised to consider the possibility of swine flu when examining returning travellers and visitors to the UK who are suffering from flu-like symptoms.
Port health representatives are offering guidance to any returning passengers who are experiencing illness.
High standards of hygiene and infection control measures have been recommended by the HPA to help minimise the risk of transmitting the virus.
Washing hands regularly and covering the nose and mouth when coughing and sneezing will help reduce the chances of the illness spreading, the health body said.
The HPA added that swine influenza cannot be transmitted through pork or pork products.