HONG KONG (Reuters) - The retail arm of Hong Kong billionaire Li Ka-shing's Hutchison Whampoa said it has agreed to sell its 50 per cent interest in a travel services business to joint-venture partner Nuance Group AG for an undisclosed sum.

AS Watson Group said the sale is expected to be completed by the end of June. "We see this deal as an opportunity for us to focus on our core retail operations, as we continue to expand rapidly in Asia and Europe," AS Watson managing director Dominic Lai said in a statement late on Thursday.

The Nuance-Watson joint-venture operates 46 stores in Hong Kong, Macau, mainland China's Zhuhai special economic zone, as well as Singapore and Malaysia. It offers travel-related services primarily in airports, and also at duty-free stores in downtown shopping malls.

Singapore state investor Temasek Holdings in March agreed to buy just under a quarter of AS Watson for about US$5.7 billion (S$7.2 billion) - its single biggest investment and one that would boost its exposure to Asia's fast growing consumer sector.