South Korea's Hyundai announced Tuesday it plans to invest 80.7 trillion won ($73 billion) by 2018 in bolstering overseas production and developing next-generation cars.

The auto giant said it would over the next four years invest 49.1 trillion won on expanding corporate infrastructure and an additional 31.6 trillion won on R&D.

That means the firm - South Korea's top carmaker - would spend an average of 20.2 trillion won each year, more than the annual record of 14.9 trillion won in 2014. 

Hyundai, along with its smaller subsidiary Kia, is the world's fifth-largest automaker.

"By investing such a record amount, we are planning to focus on securing core technologies in environmentally friendly cars, smart cars and other next-generation cars," Hyundai said in a statement.

As part of the plan, Hyundai will spend 11.3 trillion won on developing environmentally friendly models such as electric-powered or hybrid cars.

An additional 2 trillion won will be spent developing Internet-­enabled "smart cars," it said, adding it would be hiring more than 7,000 new researchers and engineers.

A sizeable portion will also be spent on building new plants in countries including China and Russia and building new headquarters, it said.

The company spent a whopping $10 billion in 2014 to buy a large plot of state-owned land in Seoul where it plans to build the giant main complex.

It also announced on December 30 a plan to build two more plants in China - the world's top auto market where Hyundai currently operates three plants.

Hyundai has for the past decade steadily expanded presence in the global market including the US, nipping at the heels of Japanese giants like Toyota and Honda.

But the firm has struggled in recent years as a weak yen blunted its price competitiveness against the Japanese rivals in overseas markets.

Hyundai said they aimed to sell 8.2 million vehicles in 2015 - a 2.5 percent increase from a year ago and the slowest growth in more than a decade.