Samudera Shipping returned to profit in 2017 but sees tougher competition in the year ahead as rivals join forces in an oversupply market.

"While recent indicators point to improving conditions in the container shipping industry, the group expects competition to heat up in 2108," the company said in its 2017 earnings summary.

"In addition, with new tonnage in excess of demand entering service in the coming year, intense competition for cargo will persist," Samudera said.