China's exports fell more than expected in June as global demand remained stubbornly weak and as Britain's decision to leave the European Union clouds the outlook for one of Beijing's biggest markets.

Imports also shrank more than forecast.

This indicates the impact of measures to stimulate growth in the world's second-largest economy may be fading, after encouraging import readings in May. 

Exports fell 4.8% from a year earlier, the General Administration of Customs said today, adding that China's economy faces increasing downward pressure and the trade situation will be severe this year. 

Chinese imports dropped 8.4% from a year earlier. 

That resulted in a trade surplus of $48.11 billion in June, compared to forecasts of $46.64 billion and May's $49.98 billion. 

Economists polled by Reuters had expected June exports to fall 4.1%, matching May's decline, and expected importsto fall 5%, following May's 0.4% dip. 

The marginal import decline in May was the smallest since late 2014, and had raised hopes that China's domestic demand was picking up. 

"The world economy still faces many uncertainties. For example, Brexit, expectations of an interest rate hike by the Federal Reserve, volatile international financial markets, the geopolitical situation, the threat of terrorism - these will affect the confidence of consumers and investors globally and curb international trade," customs spokesman Huang Songping said. 

"We believe China's trade situation remains grim and complex this year. The downward pressure is still relatively big," he added. 

Exports to the US - the country's top export market - fell 9.9% in the first half year-on-year, while shipments to the European Union - its second biggest market - fell 4.4%. 

Fresh weakness in the yuan currency appears to have done little so far to help China's struggling exporters. 

The yuan fell about 3% against the dollar and 5.8% against a broader basket in the second quarter, though Chinese officials have said repeatedly they will not purposely devalue the currency to boost exports.