Choi Son Hui, North Korea's foreign ministry director general for US affairs, spoke briefly with reporters on Saturday in Beijing on route to Pyongyang.
Choe did not specify what conditions would be needed for a dialogue with the Trump administration.
Whether the delegates from the two Koreas will meet at the forum remains to be seen, but it would still mark a rare occasion for such an opportunity as the communist North has always been shunned from such forums amid worldwide sanctions over its military provocations, including a series of nuclear tests.
In a press statement attached to its letter, North Korea's UN mission accused the United States of trying to intimidate countries into fully implementing UN sanctions by "openly threatening that they would be faced with "strong measures of sanction" by the USA".
US President Donald Trump said earlier this month that he would be "honoured" to meet North Korean leader Kim Jong Un "under the right circumstances".
Such rhetoric contrasts sharply with the tensions between the United States and North Korea.
Trump previously warned that the United States and North Korea could "absolutely" go to war in a "major, major conflict" over the communist state's nuclear threat.
The current US strategy on North Korea appears to be one of pressure and isolation.
Guns, gold and gas: What UN sanctions target North Korea?
This North Korean cargo ship found itself boarded for inspection in the Philippines in March 2016 after the United Nations ordered member nations to de-register any vessel owned, operated or crewed on orders from Pyongyang.
The North Korea flag flutters next to concertina wire at the North Korean embassy.
"The United States put THAAD in there as part of their "pivot against China" that was started by [previous U.S. president Barack] Obama".
It said on Tuesday that North Korea would send a delegation to the summit but gave no other details.
I will urgently try to solve the security crisis.
Of the UN's 193 countries, only 54 have presented reports on the sanctions resolution adopted in November past year and 89 have done so for a previous set of measures decided in March 2016.