The two persons have been identified as Sunil Sah (27) and Satrughna Kumar Sah (18), who are residing in different locations of Kathmandu Valley at present.
They were arrested from Kharibot in Kathmandu Municipality as they were in possession of a huge cache of the firecrackers of various brands, police said.
It is illegal to import, transport and sale firecrackers within Nepal and those involved in trading the firecrackers face legal action.
Earlier on Friday, police had arrested three Nepalese nationals who were in possession of a huge cache of firecrackers from Sanepa of Lalitpur district, adjoining to Kathmandu.