Chinese customs officers in eastern Shandong province have seized 60,000 maps that 'mislabelled' the self-governed island of Taiwan, which Beijing claims as part of its territory.

The maps, authorities said, also 'omitted important islands' in the South China Sea, where Beijing's claims overlap with those of its neighbours, including the Philippines and Vietnam.

The 'problematic' maps, meant for export, cannot be sold because they 'endanger national unity, sovereignty and territorial integrity' of China, authorities stated.

Maps are a sensitive topic for China and its rivals for reefs, islands and outcrops in the South China Sea.

China Customs noted that the maps also did not include the controversial nine-dash line, which denotes Beijing's assertion over nearly the entire South China Sea.

The nine-dash line extends hundreds of miles from Hainan province, and the seized maps failed to illustrate the maritime boundary between China and Japan.

Officials indicated the maps improperly labelled 'Taiwan province' without expounding on the specifics of the alleged mislabelling.

China views self-ruled Taiwan as its territory and has not dismissed the potential for military action to assert control over the island. In contrast, Taiwan sees itself as independent, governed under its own constitution.

Recent incidents in the South China Sea reflect ongoing tensions – with a notable encounter where a Chinese vessel allegedly rammed a Philippine government ship, escalating diplomatic strains.

China Customs did not specify the intended destination for the seized maps, but the country plays a vital role in global supply chains, exporting numerous goods worldwide.

Such confiscations of 'problematic maps' are not uncommon; however, the number seized in Shandong marks a significant instance. Earlier this year, different customs officials seized 143 nautical charts featuring significant border errors.

The Philippines and Vietnam particularly react strongly to representations of the South China Sea on maps. Recently, controversies arose when the Barbie movie sparked outrage for inaccurately depicting the contested waters.