The winner will meet Assange at the Embassy of Ecuador in London which has been his home since 2012.
"This is your opportunity to meet and have lunch with one of the most compelling and controversial figures of our time - Julian Assange... Over lunch you will discuss global political and security issues," the auctioneer said on its website adding that Assange will also give the winner security tips for a laptop or mobile device.
"Children are a vulnerable group: a group that needs nurturing. As a father, it pains me deeply to think of the great number of children who die without access to medicine, clean water and food: an entirely preventable problem," Charitybuzz.com quoted Assange as saying.
Assange, 43, was given shelter at the Embassy of Ecuador in June 2012 after a British court ruled to extradite him to Sweden over alleged sex crimes. Assange said he considered Sweden's accusations a pretext to evetnually send him to the United States, which is seeking to get hold of Assange for the leakage of classified documents. However, Washington has not formally charged Assange with a crime or issued an extradition request for him.