Loggers are using computer hackers to overcome modern measures to prevent illegal logging in the Amazon, Greenpeace has claimed.

A report from the environmental NGO says 107 logging and charcoal companies have used hackers to issue forged transport permits in the Brazilian state of Pará, where the environment ministry uses an online computer system to monitor and track timber.

The permits are required for any timber exported from the state, and when companies export their quota of timber from the Amazon no more permits are issued.

However, Greenpeace said hackers are being employed to “fiddle the records” and allow more timber to leave the state than is permitted. It believes nearly 1.7 million m³ of timber has been illegally removed due to forged transport permits.

“By hacking into the permit system, these companies have made their timber shipments appear legal and compliant with the forest management plans,” said André Muggiati, Greenpeace campaigner in the Amazon.

“But in reality, they’re trading illegal timber which is making the problem of deforestation worse.”

Mr Muggiati added Greenpeace’s concerns in Pará are “only the tip of the iceberg”, with a similar computer system used in two other Brazilian states.