The US military will also roll out "strategic assets" to the South following the North's missile test late Friday, Seoul's defence minister said.
Under the leadership of the ousted Park Geun-Hye, many parts of the THAAD defence system were brought into the country, but new leader Moon Jae-In refuted the programme last month, indicating the need for a new environmental impact assessment.
We will soon start consultations on the tentative deployment of the remaining components of the THAAD battery in response to Pyongyang's recent test, Defence Minister Soong Young-Moo told journalists.
The THAAD battery is composed of six interceptor missile launchers. Two launchers have been tentatively deployed at a golf course-turned-US military base in Seongju County.
A senior official at the presidential Blue House said Seoul had also informed Beijing of the decision. China denounces the US move said it will destabiliser the region and escalate the tensions.
Seoul's defence minister did not provide details on the "strategic assets" the US planned to send to the Korean peninsula and the surrounding area. The phrase normally refers to high-profile weapons systems, such as stealth bombers and aircraft carriers.
The South's defence ministry also released a video of a newly developed ballistic missile which it said was one of the world's "most accurate and powerful" weapons and capable of striking "any target in the North at any time and any place".