The seal had been in an out of the water along an 8km stretch of the coast between Takapuna and Mairangi Bay.
DoC had received a number of calls about the seal from members of the public, Mr Hirst said.
"A marine ranger has been consulting seal experts at DoC and the New Zealand Centre for Conservation Medicine at the Auckland Zoo about the seal.
"Their expert advice is that the seal should be left alone as it as access to the sea and is able to return to the water if it chooses."
Auckland Zoo said it appeared quite skinny, but this appeared to be from natural causes.
DoC requested people stayed at least 20m away from the seal and kept their dogs away from the seal and on a lead.