My opinion is no, assuming you're meaning taking off and landing only on land or water for your 3 takeoffs and landings, but I don't have a regulation to back that up. With an amphib, you could potentially get yourself into a position where you're not current in either land or sea. You might have all the requisite takeoffs in one class and all the landings in another.
Along the same lines, what certificate(s) do you need to operate it? If you only take off and land on land you need an ASEL or AMEL. I know a guy who had a Cub on amphibs and he didn't hold an ASES for several years after he bought it. He just flew it around locally and landed at the airport (a waste, I know). Ironically, he didn't have a tailwheel endorsement for many years either, despite having plenty of time in a PA11.