The inclusion of pieces of plastic in Nestle's top-selling brand Kit Kat has forced the Swiss food and nutrition products manufacturer to voluntarily recall at least four of its variants in eight countries.

The variants Peanut Butter, Hazelnut, Choc Fudge and Caramel flavour chocolate bars, weighing 48 grams each, along with Kit Kat Chunky Collection Giant Eggs, were being recalled from the United Kingdom, from where the customer complaints came from, as well as from Austria, Canada, Germany, Malta, Philippines, Singapore and Switzerland.

Reports flaunted that seven patrons in the United Kingdom found pieces of plastic in the product. It apparently came from the moulds that created the Kit Kat Chunky shape.

The moulds have been replaced, Chris Hogg, company spokesman, said.

"So far, we have not received any other similar complaints, but to avoid any risk whatsoever to our consumers, we have decided to voluntarily recall the entire production of these four Kit Kat Chunky varieties and Kit Kat Chunky Collection Giant Egg manufactured from September 2012," the company said in a statement.

The specifically affected chocolates include:

1). Kit Kat Chunky Peanut Butter (48g), expiry within September 2013 to February 2014;

2). Kit Kat Chunky Hazelnut (48g), expiry within September to October 2013;

3). Kit Kat Chunky Choc Fudge (48g), expiry within September to October 2013;

4). Kit Kat Chunky Caramel (48g), expiry within June to July 2013;

5). Kit Kat Chunky Hazelnut Multipack, expiry within September to December 2013; and,

6). Kit Kat Chunky Collection Giant Egg, expiry within before date of July 2013.

Kit Kat is one of the world's biggest selling chocolate products and one of Nestle's most important products, with annual sales hitting more than 1 billion Swiss francs or $1.06 billion. About 150 bars are consumed worldwide every second.

"The affected products have been removed from sale. The new production is not affected by this problem," Mr Hogg told Dow Jones.