ABTA has issued updated swine flu guidance for members as the World Health Organization (WHO) raised its alert level to the maximum of six.
The WHO said the increase did not mean the virus has become more virulent, but that it has a wider geographical spread.
The number of cases has increased in Europe, the US, Australia and South America.
ABTA has updated a letter for members to issue to their foreign suppliers and post on customer noticeboards to keep them updated on the situation. The letter is available at abta.com.
The Foreign Office has not altered its travel advice.