It is asking reserves in the South East of England, East Anglia and Northamptonshire to undertake patrols for dead wild birds.
Defra said the areas identified for increased surveillance are those into which birds migrating from the affected parts of Europe are most likely to arrive.
Chief veterinary officer, Debby Reynolds, said: "The risk of AI to the UK remains low but increased, and our current control and monitoring measures reflect this. We will continue to monitor the disease situation and we are keeping our levels of surveillance under review.
"We are also very grateful for the valuable voluntary contribution from the organisations who we work in partnership with to carry out this surveillance work."