Direct investment in Korea by Japanese companies shot up last year on the back of the weakening yen to surpass US$4.5 billion, the Financial Supervisory Service said on Tuesday.

This is a record high and a dramatic up-shift from the previous two years, when the figure stood at $2 billion and $2.2 billion, respectively.

Japan ranked first among countries that invested in Korea in 2012, making up 27 percent of total FDI.