BEIJING-- China's State Administration of Taxation (SAT) said on Monday that a widely-circulated document concerning revisions on the country's individual income tax law was forged.

"Some individuals forged the SAT's name and published a document on issues related to the implementation of the revised individual income tax law, which seriously misled taxpayers," the administration said in a notice.

The SAT was commenting on media reports that claimed the SAT released a document on July 29 after the central government adopted an amendment to the individual income tax law. According to the reports, the SAT would use a new mathematical formula for tax calculation. The document specified how taxpayers would be subject to the old and new tax rates during different times of the tax year.

"The SAT has never published such a document nor made any elaborations; the document and alleged elaborations were forged," the notice said.

The administration did not give any explanation on the forgery but said those guilty will be held accountable according to laws.

The State Council announced on July 27 amendments to the country's new individual income tax law, including raising the monthly tax exemption threshold from 2,000 yuan ($312.5) to 3,500 yuan.