South Korea's corporate regulator said Monday it will begin an antitrust review of a $4 billion deal by Germany's Delivery Hero to acquire the nation's largest food delivery app operator, Woowa Brothers.

The Fair Trade Commission said it has received documents from the two firms for an antitrust review, which could take at least 120 days.

The FTC will review whether the planned acquisition would hurt competition in the nation's food delivery app market.

An FTC official said the regulator will "closely review" the planned acquisition in line with the nation's law on fair transactions.

On Dec. 20, Joh Sung-wook, chairperson of the FTC, said the regulator "will take a balanced approach (to the deal) by making a comparison between negative impacts on consumer welfare and promotion of innovation."

Earlier this month, the German firm, which also has the second-biggest delivery player in South Korea, Yogiyo, under its wing, said it will acquire an 87 percent stake in Woowa, the operator of delivery app Baedal Minjok, or Baemin, from existing investors, such as Goldman Sachs and Singaporean fund GIC.

Founded in 2010 as a food delivery company, Woowa Brothers quickly became the country's top online food delivery services firm, enjoying over 10 million active monthly users in a country with a population of 51 million. Woowa Brothers' Baemin accounted for up to 60 percent of the market.

But the combined users of Yogiyo and Baemin will account for 98.7 percent of all users of food delivery-related apps in Asia's fourth-largest economy, triggering concerns that the megadeal would hamper competition in the fast-growing market.

South Korea's food delivery app market reached 10 trillion won ($8.6 billion) last year.

Woowa Brothers and Delivery Hero signed a partnership to establish a joint venture, named Woowa DH Asia and to be based in Singapore, to tap into the burgeoning food delivery market in the region. (Yonhap)