GlaxoSmithKline plans to buy up to an additional 31.8% stake in its Indian consumer products arm for about $940 million, as Britain's biggest drugmaker deepens its emerging markets and non-prescription consumer health footprint.

The move is the latest in a series of deals by GSK to increase its presence in f ast-growing economies a nd reduce its reliance on traditional pharmaceuticals in Western co untries where sales are slower.

GSK aims to raise its stake in GlaxoSmithKline Consumer Healthcare to 75% from 43.2%, paying 3,900 rupees ($70.16) per share through an open offer, it said in a statement.

"This transaction represents a further step in GSK's strategy to invest in the world's fastest growing markets," said David Redfern, chief strategy officer at GSK in London.

The company, however, has "no current plans" to launch an open offer for its Indian drugs unit GlaxoSmithKline Pharmaceuticals, he added.

GSK said the t ransaction - to be funded through existing cash resources - w o uld be earnings neutral for the first year and bo ost earnings th ereafter. It will no t impact expectations for the gro u p's long-term share buyback programme.

Horlicks plan

Tough market conditions in Europe have hampered GSK's hopes for a return to sales growth this year, although the company's growing business in emerging markets and its large consumer healthcare operation are both doing well.

In India, for example, sales of the consumer unit's flagship Horlicks brand stood at 270 million pounds ($432 million) in the year that ended December 2011, contributing to nearly three-quarters of its total revenues.

"A lot of the current business of Horlicks is in the south and the east of India. So there is still a great opportunity to increase the penetration to the north and the west," Redfern told Reuters in an interview, adding that the company intended to introduce new variants of the brand in the country.

GSK does not plan to delist the unit.

Securities regulations in India require a minimum public shareholding of 25% for a company to maintain a public listing.

The offer period is expected to begin in January 2013.