Where did the name Orewa (New Zealand) come from?

It is undoubtedly of Maori origin, although I can find no absolute explanation. The paper cited below suggests that, for place names starting with 'O', "the part in these names which comes after the 'O' is a proper name, the name of a person; that such names are similar to those we give to localities known principally as the dwelling-places of persons who are well known as residents in such localities." If this supposition is correct, Orewa would be the place where Rewa lived.

http://rsnz.natlib.govt.nz/volume/rsnz_25/rsnz_25_00_004730.html

"Kaiorewai" is the Moari name of the Orewa Estuary.
"Orewa" may or may not be a shortening of this name.
I am interested how many possible other origins.
"Ore" (Red) is the Moari name for Red Beach. So named because buried shells buried in the beach are stained black by iron dissolved in the ground water seeping out from the land. When uncovered by storms eroding the beach the shells soon turn various colours of red as the iron sulphides oxidize.
Small canoes could be safely landed behind the small reef at the north end of Red Beach so avoiding the treacherous estuary entrance. Kiaorewai may or may not be loosely translated as Kia-Ore-Wai "there is food" Kai "behind the Red Beach" Ore "in the estuary" Wai.

The names "Ore" and "Kaiorewai" known to original Dairy Flat settler families (Stoneham, Curle, and others) who described gum diggers camping on the banks of the Kaiorewai and living on damper and shell fish. Large quantities of gum were dug from the estuary. There were no mangroves in the estuary at that time.(These early Dairy Flat settlers nearly starved).
The gum diggers had dug a drinking water point into the sand stone just above sea level in a small stream which ran from Moari Hut Road. This water point could still been seen cut into the sand stone in the 1950's but has probably eroded away by now.

The name "Crocodile Island" was used by the settlers at that time. Simply because the island looked like a crocodile when seen from the hill at the south end of Orewa.