International logging companies have used a loophole in Liberian law which grants them access to as much as one quarter of Liberia's landmass, according to a watchdog.
Global Witness said in a report that foreign companies are relying on so-called "Private Use Permits", designed for use by private landowners to allow them to cut trees on their own property.
These permits are instead being used by major companies and now cover 40% of the country's forests, according to the report which was co-authored by the Save My Future Foundation and the Sustainable Development Institute.
Companies holding the permits are not required to log sustainably, and pay little compensation to the government for the right to export the timber.
They include companies linked to Malaysian logging giant Samling, which along with its subsidiaries has been involved in cases of alleged illegal logging in countries around the world from Cambodia to Guyana to Papua New Guinea.
Samling said that it was "surprised" by Global Witness's report, adding that Samling "does not have a presence in Liberia".
Over the weekend, Liberian president Ellen Johnson Sirleaf suspended the head of the country's forestry authority, Moses Wogbeh.
Presidential spokesman Jerolinmek Piah told the AP on Monday that Mr Wogbeh is under investigation into an allegation that he violated a land permit issuance moratorium put in place in February.
Such a permit grants land to people to carry out logging activities commercially.
On Tuesday after the report came out, Liberian information minister Lewis Brown thanked London-based Global Witness for drawing attention to the issues. He said: "The Private Use Permits have been considered in the past to assist communities in terms of job creation, in terms of support and benefit - but the truth is, we are finding out also, that it has been abused and it is unacceptable."