Four tugboats have been deployed to rescue a post-panamax bulker that ran aground for a second time this week in South America's Parana River, where low water levels have hampered grain transport.

According to Alpemar Shipping Agency, the 81,531-dwt Cofco 1 (built 2014) first grounded about 465km up the river late on Monday before being refloated by a tugboat.

The Cosco Shipping Bulk-owned ship ran aground again about 7km northwest of San Pedro, Argentina, early on Wednesday.