"Only if the sanctions on [North Korea], these barriers expressing discrimination and distrust, are removed can the six-party talks resume," Choe said.
"If the sanctions are lifted, then the six-party talks can resume immediately. The key word is immediately."
North Korea pulled out of six-party nuclear disarmament talks in April 2009 saying it plans to restart its Yongbyon nuclear reactor.
The previous and current US administrations have said that Washington can discuss a peace treaty once the North ends its nuclear arms programme, considered one of the biggest security risks in the region.
Kim Tae-young, the South Korean defence minister, was sceptical about the North's peace treaty proposal.
"There have been many cases where North Korea has made a gesture of peace while stepping up its provocations," he said in Seoul.
"Our military should promote peace talks but we are always aware that North Korea can create provocations in any situation."
A similar statement from the North Korean foreign ministry on Monday was rejected by both South Korea and the United States, both maintaining that the denuclearisation of the North must precede the removal of sanctions.
Against this backdrop, North Korea's military has told South Korea to stop activists from launching anti-Pyongyang propaganda leaflets in balloons across the border, or face some form of retaliation.
The South Korean government said it cannot prevent activists from sending the leaflets citing freedom of speech, but has urged them to stop so that they don't damage ties between the two Koreas.
|The North's military wants South Korean activists to be immediately punished [AFP]
The two Koreas had agreed in 2004 to end decades of propaganda warfare across the Demilitarised Zone dividing the neighbours.
The North's military, in a separate statement carried by the official Korean Central News Agency, said it "will never tolerate even the slightest acts" of undermining "our leadership's absolute authority".
"The separatists at home and abroad will never be able to flee from a stern punishment by the nation for challenging history," said the English-language statement, which also demanded the activists be immediately punished.
On New Year's Day, about 70 South Korean activists tied thousands of leaflets condemning Kim Jong-il, the North Korean leader, to balloons and launched them across the border.
Some protesters also burned large North Korean flags with Kim's picture printed on them.
"We'll continue to send leaflets because we must convey voices of hope to our North Korean compatriots," Choi Woo-won, an activist and university professor who helped organised the leafleting, said on Wednesday.
"We must help North Koreans to develop the power to rise up against the Kim Jong-il regime."