The structure was discovered while local authorities were inspecting an illegally constructed building in the An Duong Industrial Park, said Pham Van Moi, head of Hai Phong economic zone's management committee.

Moi said that the paved walkway, which surrounds an artificial lake, was located on a land lot meant to grow greenery in front of the Chinese-owned Tham Viet Company's executive building.

When seen from above, the walkway was found to resemble the nine-dash line, a demarcation line used by China to represent its illegal claims in the East Sea, known internationally as the South China Sea, violating Vietnam's sovereignty.

He said Hai Phong authorities have ordered Tham Viet Company to swiftly demolish the walkway, level the ground and restore it to its original state as park land.

"If the company does not do, the city will enforce it," Moi said.

The Tham Viet Company has also been ordered to dismantle a 400-square-meter (480-square-yard) building it built illegally on a land lot meant for greenery at the edge of the An Duong Industrial Park, according to Le Anh Quan, Party secretary and chairman of An Duong District.

This building was the original object of the authorities' inspection and had been used to house the company's Chinese workers for the past few months.

On Tuesday evening, vice chairman of An Duong District Le Van Cuong confirmed that Tham Viet Company had finished dumping land to fill the artificial lake and was in the process of dismantling the illegally constructed building, with work expected to be completed Wednesday.

The Chinese company was first discovered to have built dozens of houses for its Chinese workers on land meant for green spaces last September. Local authorities had demanded then that the illegal structures are dismantled, but the company had only complied partially.

The An Duong Industrial Park in the namesake district was founded in 2008 with a total area of about 800 hectares (2,000 acres). It was developed by the Tham Viet Company with an investment of $175 million.