North Korea "is now earnestly examining even the issue of suspending the operation of its nuclear facilities earlier than expected, that is from the moment the first shipment of heavy oil equivalent to one-tenth of the total quantity is made," the North's Foreign Ministry said, according to the country's official Korean Central News Agency.
It is the first time that North Korea has made any comment on the shutdown timing.
South Korea said earlier Friday that a first shipment of 6,200 metric tons of fuel oil will be sent to the North on July 12.
That is more than one tenth of the 50,000 tons.
Implementation of the February disarmament deal has been delayed because of a banking dispute with the United States. That row was fully resolved last week.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969