CANBERRA: US corn futures edged higher on Thursday, hovering near a more than seven-year high, as the market awaited data expected to confirm strong Chinese demand for US supplies.

Soybeans inched down despite concerns over supplies in South America, while wheat also edged lower.

The most-active corn futures on the Chicago Board Of Trade were up 0.2% at $5.53-1/2 a bushel by 0440 GMT. Corn rose 1.7% on Wednesday and hit a June 2013 high of $5.54 a bushel earlier this week.

Analysts said corn remains underpinned by strong export demand out of the United States, although market activity remains cautious ahead of what is expected to be official confirmation of Beijing's demand.

The US Department of Agriculture (USDA) will release its latest weekly export sales report on Thursday. It is expected to show record corn sales after a spate of large sales.

"China's purchases of US corn continue to be large but have not yet surfaced in the USDA's data net," said Tobin Gorey, director of agricultural strategy, Commonwealth Bank of Australia.

The most-active wheat futures were down 0.2% at $6.47 a bushel, having ended 0.5% higher on Wednesday.

The most-active soybean futures were down 0.1% at $13.69-1/2 a bushel, having closed 1.2% higher on Wednesday.

The decline in prices came despite South American supply issues.

Argentine agricultural exports were disrupted on Wednesday as truckers blocked roads around the Buenos Aires ports of Bahia Blanca and Quequen and authorities cleared roads near the country's main export hub of Rosario.

In Brazil, a rain-hampered start to the soybean harvest was also raising doubts about how soon Brazilian exports will be available to help meet Chinese demand.