Britain's MHRA drug regulator has halted the sale of 16 medicines made by Wockhardt after it identified manufacturing deficiencies at the Indian group's Waluj factory.

Though the Medicines and Healthcare products Regulatory Agency said there is no evidence that the products are defective and that patients who already have the medicines do not need to return them, pharmacies, dispensing clinics and wholesalers have been asked to stop selling them.

"This is not a patient-level recall because, though the medicines that are affected have not been manufactured to Good Manufacturing Practice (GMP) standards, there is no evidence of a patient safety risk from medicines that have been sold in the UK," the agency said on Thursday.

"However, the MHRA has to act in the interests of public health as poor manufacturing standards cannot be allowed to continue."

A statement from Wockhardt said that the one-off impact of the MHRA recall would be about 1.5 million pounds ($2.2 million) and that exports out of the Waluj plant constituted less than 5% of its total sales in Britain and less than 2% of the group's overall sales.

The manufacturing standards at the Waluj factory were not mentioned in the company's statement.

The medicines affected by the precautionary recall include those used for the treatment of infections, high blood pressure, diabetes, epilepsy, depression, schizophrenia, Parkinson's disease, thyroid conditions and dementia in Alzheimer's patients.

A number of top Indian generic drugmakers have faced compliance issues over the past two to three years, mainly because of investigations by the United States Food and Drug Administration (FDA).

Wockhardt's Waluj plant was put on an "import alert" by the FDA in May 2013.

At the time, Wockhardt said that the FDA's action potentially affected $100 million in revenue on an annualized basis, but that it should be able to restore most of that within nine months by shifting production to other facilities.

An "import alert", effectively a ban, results in the detention of drugs, without physical examination, from companies that have not met so-called good manufacturing practices, the FDA website says.

The MHRA said that the deficiencies it found in Wockhardt's medicines were identified during a routine inspection in March. It found a low risk of cross-contamination because of poor cleaning practices and defects in a ventilation system.

The regulator said there was also evidence of forged documents relating to staff training records.

India exports pharmaceutical products worth about $12 billion every year and the country is seen as a key sourcing destination for generic drugs by regulated markets such as the United States, Europe and Japan.