The outlook for China's economy has been boosted by stronger-than-expected growth for both exports and imports last month.

Key points: China's trade surplus expands to $US42.8b

China's trade surplus expands to $US42.8b Iron ore imports up 15.4pc on a year ago

Iron ore imports up 15.4pc on a year ago Strong global demand likely to underpin export growth into the second half of 2017

Firmer global demand lifted June exports by 11.3 per cent in US dollar terms, up from the 8.7 per cent growth in May.

In local currency terms, the value of exports grew by 17.3 per cent.

Domestic demand also showed surprising vigour, with imports rising by 17.2 per cent (in $US) over the month.

The growth in imports is good news for Australia's miners, with iron ore shipments up by 15.4 per cent on an annualised basis, up from 5.5 per cent growth in May.

Oil imports also jumped sharply, to be 16.4 per cent higher over the year.

Chinese economy steadying

ANZ's senior China economist Betty Rui Wang said ongoing infrastructure investment was likely to stabilise China's economic growth going into the second half of the year, leading to solid demand for raw materials.

Ms Rui Wang said there were also promising signs in the larger trade surplus recorded in June.

"The persistent trade surplus, together with investment inflows, could help relieve the pressure from capital outflows," she said.

"Outbound direct investment seems to have lost momentum, contracting for six consecutive months since January, while foreign direct investment seems to have gradually recovered of late."

Capital Economics analyst Julian Evans-Pritchard said the figures were generally upbeat and pointed to still strong foreign demand for Chinese goods, as well as fairly resilient domestic demand.

"Looking ahead, exports should continue to do well given the relatively positive outlook for China's main trading partners.

"But we are sceptical that the current pace of imports can be sustained for much longer given the increasing headwinds to China's economy from policy tightening," Mr Evans-Pritchard said.

China's trade bounce

June ($US) May ($US) Market forecast ($US) Exports +11.3pc +8.7pc +8.9pc Imports +17.2pc +14.8pc +14.5pc Trade balance +$US42.8bn +$US40.8bn +$US42.6bn

Source: National Bureau of Statistics