April 27 (Reuters) - The Brazilian government is looking at ways to perform more effectively the challenging task of tracing the origins of cattle raised for slaughtering, Carlos Favaro, agriculture minister of the world's biggest beef exporter, said on Thursday.

It is crucial for buyers such as meatpackers to know the exact origins of Brazil's cattle as the country's law makes it a crime to ranch cattle on illegally cleared woodland.

President Luiz Inacio Lula da Silva has promised to crack down on environmental crimes, and verifying cattle origins is key to ensure animals do not come from areas of deforestation in the Amazon or the Cerrado savannah.

"The format and the model is up for discussion," Favaro told reporters on the sidelines of a beef industry event, referring to the proposals for verifying the origins of cattle.

"It must be step by step," he said, citing obstacles such as lack of internet connectivity in certain remote areas where cattle is raised. "We cannot demand something from the farmers which they are not prepared for."

Any system which is not verifiable would lack credibility and would amount to "greenwashing," Favaro said, adding it would not help Brazil to open up new markets for its meat.

Brazilian Vice-President Geraldo Alckmin told the same event that land grabbers, not farmers, are guilty of deforestation in the Amazon rainforest. (Reporting by Ana Mano; Editing by Leslie Adler and Muralikumar Anantharaman)