Seoul (Reuters) -South Korea and the country's auto association requested on Monday relief from a U.S. plan to levy port fees on all foreign-built vehicle carriers, saying it would add a significant burden to a car industry that has pledged big investments in the United States.

The U.S. Trade Representative announced the fees on April 17 as part of an ongoing effort to penalise some China-linked ships calling at U.S. ports with fees to fund a domestic shipbuilding revival and counter China's dominance on the high seas.

The fees have sent shockwaves though the vehicle carrier industry, because they go beyond targeting Chinese-built and Chinese-owned ships.

The Korea Automobile & Mobility Association, which represents Hyundai Motor, Kia and the South Korean units of General Motors and Renault, also raised concerns that the fees would impose "additional financial burdens on imported automobiles that are already subject to 25% tariffs," according to its comments submitted to the USTR.

"Such a measure risks imposing undue costs on companies, workers and consumers in both countries," South Korea's trade ministry and maritime ministry said in separate comments.

The auto association also highlighted Hyundai Motor Group's $21 billion investment plan announced by its chairman and U.S. President Donald Trump at the White House in March.

The rule "may in turn adversely impact the contributions that Korean firms are making to U.S. commerce," it said.