The Taoiseach says Ireland will fight the Mercosur trade deal unless Brazil protects the Amazon rainforest, which is on fire.
The controversial deal would see almost 100-thousand tonnes of beef from South America enter the EU every year.
Leo Varadkar has also criticised the Brazilian President for claiming that environmental groups were starting the fires to make him look bad - describing it as 'Orwellian.'
Satellite images show a surge in fires since Jair Bolsonaro took power and promised to develop the region for farming and mining.
The French President says the rise of fires in the forest is an international crisis.
Emmanuel Macron wants world powers to urgently discuss the issue at a G7 meeting tomorrow.
But Bolsanaro is accusing him of interfering.
The smoke is visible from 400 miles up in space.