Brazil's President Dilma Rousseff warned Thursday that she will not all environmental protection to be eroded, after a pro-agribusiness congressional panel backed changes to the new forestry law.

"We are a country which has major strength in this area. It is of the utmost importance that we honor the commitments with respect to the environment," she said at the end of a speech to business and government officials.

She criticized the decision by the congressional committee to approve amendments to a new forestry code approved by lawmakers in April.

"The government is open to the negotiations, but cannot assume responsibility for negotiations in which it is not involved," she warned.

The Folha news agency quoted Environment Minister Izabella Teixeira as saying the amendments adopted Wednesday amounted to "a step backwards".

In April, the powerful agribusiness lobby secured what was seen as a victory in its long-standing feud with environmentalists when Congress approved an overhaul of the 1965 forestry law.

Rousseff removed 12 controversial articles and made 31 modifications to the text to ensure that areas of the Amazon and sensitive ecosystems remained under legal protection.

The legislation maintains the obligation to protect 80 percent of the forest in rural areas of the Amazon and 35 percent of the sertao, or arid hinterland of northeastern Brazil.

But it eases restrictions for small landowners who face difficulties in recovering illegally cleared land.

Environmentalists say the law will lead to further deforestation in the Amazon, home to the world's largest collection of plants and animals.