The Medicines and Healthcare products Regulatory Agency (MHRA) said fake tablets with the batch number 067404K3 were in NHS circulation after it recalled batch number 004405K1 last month.
The agency advised patients to stop taking the tablets and contact their pharmacist.
Both batches carry authentic Lipitor numbers, so patients will be unable to tell whether their tablets are fake or real.
Early tests on the batches suggest that they contain a similar substance which is not thought to pose any risk to health.
In a statement, the MHRA said: "The MHRA has detected a new batch of counterfeit Lipitor tablets in the supply chain with a different lot number to that covered by our recall notice on July 19. The MHRA, in conjunction with Pfizer Ltd, is now recalling Lipitor 20mg tablets bearing the lot number 067404K3.
"In July 2005 the agency recalled a specific batch of counterfeit Lipitor 20mg tablets (lot number 004405K1) and reissued this safety warning on July 19 2006 after further packets belonging to this batch were found.
"Any patient who has the Lipitor 20mg product with lot number 067404K3 or lot number 004405K1 should stop taking the tablets and contact their pharmacist."
It said further testing is going on and patients should leave 24 hours between taking their last tablet and the first tablet of a new supply.
Danny Lee-Frost, head of enforcement at the MHRA, said: "The testing of the counterfeit product indicates there is no immediate risk to patients."
More than a million Britons are believed to take Lipitor for cardiovascular conditions.