Johnson & Johnson is voluntarily recalling about 32 million packages of its birth control pill Cilest in Europe, Asia and Latin America, a spokeswoman said late on Tuesday, the latest in a string of recalls over the past two years.

Cilest is manufactured by Janssen Pharmaceuticals, a unit of Johnson & Johnson. Spokeswoman Michelle Romano said the recall of 179 batches was initiated because one active ingredient in Cilest did not lead to a "defined specification" in one routine internal test.

Media reports have said the tests showed one of the two hormones in Cilest was being released more slowly than intended. The pill is available in 43 countries, but is not sold in the US.

Cilest contains two hormones that are similar to the natural hormones oestrogen and progesterone. Cilest, which women use to avoid unwanted pregnancies, works by preventing the release of eggs from the ovary.

The product remains safe and effective, Romano said, adding that there is no risk for the women who had taken the pill. Less than 800,000 individual consumer packets remain available for sale, she said.

The recall, of which wholesalers and pharmacies were notified in the last week of May, involves pills that were manufactured in or after 2011. The company did not issue a formal press release announcing the recall.

"The recall is at the wholesale and pharmacy level and this is not a patient level recall," Romano said.

In the past two years J&J has recalled over-the-counter drugs, contact lenses, heart devices, and insulin pump cartridges.

In March, J&J's LifeScan unit recalled and replaced nearly 2 million meters used to measure blood glucose levels in diabetics due to a failure to operate properly at extremely high glucose readings. - Reuters