Under the act, it is now an offence to take, damage or destroy the nests of certain wild birds at any time during the year.
Biodiversity Minister Barry Gardiner said the new measures will assist the long term breeding success of birds of prey.
�The wild birds protected under these new provisions are the golden eagle, white-tailed eagle and osprey,� he said.
�As the law currently stands, all birds' nests are protected under the Wildlife and Countryside Act 1981, but only while they are in use or are being built.
�Protecting the nests of these birds year round will greatly assist their long term breeding success by protecting their nests outside their usual breeding season.
�Whilst the golden eagle and osprey are rare residents of England and Wales, it is increasingly likely that more breeding pairs will become resident, as they are all subject to re-introduction or re-establishment programmes, and there is every likelihood that the white-tailed eagle will extend its range into England in the near future.�
Wildlife inspectors and police will have greater powers to more effectively protect wildlife under the legislation, said Mr Gardiner.
�By enhancing and widening the enforcement provisions already contained in the 1981 Act, and providing an extension to the time limit to bring about legal proceedings, we are ensuring that wildlife crime can be effectively investigated and that offenders can be prosecuted.�
Welsh Minister for Environment, Planning and Countryside, Carwyn Jones, added:
"Our rich and varied wildlife is an important part of our natural environment. These new laws will ensure our wildlife gets greater protection so that it continues to thrive and can be enjoyed by future generations."
Two provisions relating to Sites of Special Scientific Interest (SSSIs) have also come into force.