South Korea's Hyundai Motor Group flagged another year of tepid car sales growth on the back of a slow 2018, saying trade protectionism added uncertainty and major markets such as the US and China remained sluggish.

In his first New Year address to employees, group heir apparent Euisun Chung said Hyundai Motor Co and Kia Motors Corp would together launch 13 new or updated models in 2019.

He also promised to complete a restructuring of South Korea's second-biggest conglomerate, which is expected to pave the way for him to succeed his octogenarian father as head of the group.

The complicated succession plans come as Hyundai contends with problems that have cost it market share in China and the US and stalled its rise up the ranks of global automakers.

It missed a boom in sport utility vehicles (SUVs), faces potential US tariffs and a US investigation over how it handled a vehicle recall, and it has lost ground in technological advances such as self-driving cars.

"Business uncertainties are heightening as the global economy continues to falter. Walls of protectionism are being constructed around the world," Chung told employees at the group's headquarters in Seoul.

"Internally, we face challenging tasks such as stabilizing business in major markets like the US and China, while simultaneously enhancing our responsiveness to drive future growth."

Hyundai Motor Co and Kia Motors Corp - together the world's fifth-biggest automaker - set what they called a "conservative target" of 7.6 million vehicle sales in 2019.

This compares with analysts' estimates of 7.3 million to 7.4 million units sold last year, the conglomerate said, or a 2.7 percent to 4 percent increase. It sold 7.25 million vehicles in 2017.

Morgan Stanley has forecast global auto production to fall 1 percent in 2019, the first drop in nine years.

"Hyundai will be launching new models, but competitors will be also doing so, making it difficult for Hyundai to increase shares in the sluggish markets in China, US and Europe," said Sean Kim, an analyst at Dongbu Securities.

The group said it would launch a premium Genesis SUV and the Sonata sedan this year, among other new models.

Hyundai would launch a pilot service of its autonomous taxi in South Korea by 2021 and expand partnerships with leading players in that area, Chung said.

Chung also pledged to "actively communicate with" shareholders, an apparent reference to US hedge fund Elliott, which effectively scuttled a previous restructuring plan last year.