"We are currently considering [the matter] in consultation with a related [government] agency," Kang said, as quoted by the Kyodo news agency.
The sanctions, also known as 5.24, were imposed by Seoul after a torpedo attack against the South Korean warship and banned economic transactions with North Korea.
Pyongyang denies it was responsible for the attack.
The situation on the Korean peninsula has significantly developed over the last few months, with North Korea's Kim promising to give up nuclear aspirations.
Kim Jong-un has held three rounds of talks with his South Korean counterpart Moon Jae-in and a historic summit with US President Donald Trump in Singapore in June.