"There were heaps of people crab hunting a couple days ago, up by the refinery entrance, the car park was jam packed. I wonder if it was them," Ayla McFadyen said.
Another said: "This is disgraceful. No respect for our Bream Bay".
Mr Davis said the crabs were bigger than the palm of a hand and were found about 100 metres from the foreshore.
He presumed they were a day old but were not smelly.
"It was pretty ridiculous. I haven't seen that many before." He believed it could have been done by a commercial crabber because of the volume.
Ministry for Primary Industries Northland District compliance manager Stephen Rudsdale said increased patrols by fisheries officers in the area last week would not have gone unnoticed.
"The only plausible explanation for the dumping is someone must have been spooked by the high presence of fishery officers in that area and decided to dump them.
"The increased presence of fisheries officers was because mussels in the Marsden Pt area were under a lot of pressure lately and also people can now get access to the beach from Rama Rd," he said.
Mr Rudsdale said it was an "awful lot" of crabs but he doubted they were commercial because of where they were found.
He said MPI saw a picture of the dumped crabs on the Ruakaka/Bream Bay buy sell swap Facebook page yesterdaybefore two fisheries officers were sent to search for the crabs but without success.
Mr Rudsdale said commercial fishermen would normally dump their catch at sea and not on land. He called for public help in locating the dumped crabs and finding those responsible.
The daily limit for paddle crabs is 50 but there are no size restrictions.
Those caught in possession of between 50 and 150 are fined between $250 and $500 while those with more then 150 could expect a fine of up to $150,000.
Members of the public can contact MPI on 0800 80 99 66.