South Korea backs six-party talks with North
South Korean President Lee Myung-Bak has said there is no choice but to try to dismantle North Korea's nuclear programme through diplomacy.
His comments came after he received his foreign ministry's annual report.
They follow a year of high tension, including exchanges of fire between North and South.
The talks format involves the two Koreas, China, Russia, Japan and the US, and had offered rewards to the North for ending its nuclear programme.
South Korea, the US and Japan have said previously said six-party talks could not resume until the North showed serious intent to change.
"(We) have no choice but to resolve the problem of dismantling North Korea's nuclear programme diplomatically through the six-party talks," said Mr Lee.
Mr Lee said time was short for the international community to make progress on ending the North's nuclear threat because North Korea has set 2012 as its deadline to become a "great, powerful and prosperous" nation.
The president's spokeswoman said Mr Lee's comments did not reflect any new flexibility on resuming the nuclear talks involving the two Koreas, the United States, China, Russia and Japan.
"Lee has repeatedly said North Korea must show substantial changes in terms of the dismantling of its nuclear programme," Kim Hee-jung told reporters, according her office.
"Regarding that, our position hasn't changed at all."
On 23 November, North Korea shelled the South Korean island of Yeonpyeong, killing four South Koreans, including civilians.
North Korea and its ally China, meanwhile, expressed anger at huge military drills mounted by the South with its main ally the United States.
South Korean reports say that North Korea has also dramatically stepped up its military drills in the past year.
Western allies of South Korea were angered by revelations this year about the existence of another nuclear enrichment plant in North Korea.
The North has again defended this, saying it was for the production of civilian power sources only and would not have been necessary if the US had kept to earlier promises to supply such facilities.
The six-party negotiations led to the closure of a plutonium-producing reactor in 2007, but collapsed in April 2009 amid mutual recriminations, after which the North set off further nuclear tests.
Lee Myung-bak also told his nation earlier this week that it must unite in the face of military aggression from the North.
Seoul also accuses the North of torpedoing a South Korean warship, the Cheonan, in March - an incident that left 46 sailors dead.
On Sunday, it was announced that South Korean and Chinese defence ministers would meet in Beijing in February for talks on the situation.