Foreign Minister Ban Ki-moon says the government will work with other parties to produce a more binding agreement at the upcoming six-way talks.

Ban on Wednesday pointed to the weakness of the chairman's statement issued at the last round of the talks.

Saying holding substantial discussions over three or four days is difficult, he said the parties this time may eliminate format limitations by extending the dialogue period or have a recess of two or three days.

On a possible change in the six-way format, Ban said the five nations excluding North Korea have reached an agreement and will hold a related meeting once the North's delegation arrives in Beijing.

While Seoul will strive for tangible results, he warned against unrealistic optimism and that related members should soon hold extensive negotiations according to Pyongyang's position.

The fourth round of the nuclear talks will open Tuesday in Beijing after a year-long hiatus.