Concerns over the destruction of the Brazilian rainforest resurfaced at the weekend after it emerged that deforestation jumped by 64% over the last 12 months, according to official government data.

Brazil's National Institute for Space Research this week said that around 3,145 square miles - an area half the size of Wales - were razed between August 2007 and August 2008.

With commodity prices hitting recent highs and loggers and soy farmers pushing ever further into the Amazon jungle, satellite images captured by a real-time monitoring system, known in Brazil as Deter, showed that deforestation was once again on the rise after three years on the wane.

The figures launched the controversy over how best to preserve the Amazon rainforest onto the front pages of Brazilian newspapers, and triggered a war of words between environmental campaigners and members of the government who claim that their struggle to protect the rainforest is not being given sufficient recognition.

"This is not about luck, it is about work, work, work," Brazil's environment minister, Carlos Minc, told reporters. News that total deforestation rose over the entire year came quickly after the announcement of monthly figures showing that month-on-month deforestation had in fact fallen. Government figures show that between May and June this year deforestation fell by 25%.

Despite the good news in recent months about the deforestation of the world's largest tropical forest slowing, Minc admitted his country still faced huge challenges in order to stamp out illegal logging and described the levels of destruction as "alarming".

"We can't celebrate [the monthly drops] because deforestation is [still] very large. We have to invest everything into sustainable development," Minc told the Folha de Sao Paulo newspaper.

Critics claimed that the annual statistics gave a more accurate picture of the destruction been wrought on the Brazilian jungle.

Environmental campaigners fear that Brazil's push to expand its economy and develop the Amazon region is posing increasing threats to Brazil's natural resources. They accuse the government of retreating from its promises to defend the Amazon rainforest, which has been decimated since the 1970s by a mixture of logging, cattle ranching and soy farming.

"The president [Luiz Inácio Lula da Silva] said there would be no steps backwards," the former environment minister Marina Silva said in an interview published yesterday in the O Globo newspaper. "But suddenly there is a conjuncture of things that go against everything that was being done."