HAIKOU - The sales of four offshore duty-free shops in South China's island province of Hainan have exceeded 30 billion yuan ($4.6 billion) so far this year, said the Hainan provincial department of commerce.

From Jan 1 to Dec 14, duty-free sales at the four locations surpassed 25 billion yuan and the sales of taxed goods reached about 5 billion yuan, both doubling last year's figures.

Starting on July 1, Hainan increased its annual tax-free shopping quota from 30,000 yuan to 100,000 yuan per person. The categories of duty-free goods have been expanded from 38 to 45, with some electronic products such as mobile phones and laptops added to the duty-free list.

The previous tax-free limit of 8,000 yuan for a single product has also been lifted, and the number of categories with a single-purchase quantity limit has been significantly reduced.

The island province has used policy upgrades to boost its economy, with its daily duty-free sales topping 120 million yuan, an increase of over 200 percent year-on-year.

By the end of 2020, the duty-free shops are expected to net about 31.5 billion yuan in total sales for the year.

Building an international tourism and consumption destination, the island province will introduce more enterprises and open more duty-free shops to unleash the effect of tax-free shopping policies.

Currently, Hainan has four offshore duty-free shops -- two in its capital city of Haikou, one in Qionghai and one in its popular resort city of Sanya.