If the target was reached, the minister gave her assurance that the land would be added to the Abel Tasman National Park and that free access would be secured for the public in perpetuity.
The minister said the campaign was inspirational and reflected New Zealanders' "deep and abiding love" for their natural heritage.
The campaign was started by Christchurch resident Duane Major, who regularly visited the private beach.
"I really value our national park and the idea of taking this opportunity to permanently take it off the private market and put it into the hands of everyone ... It's certainly worth a shot," Mr Major said.
The Department of Conservation has previously said that it was not interested in buying the site because it was not a precious ecological site, but it would be open to receiving the land.
The department could not justify spending $2 million on 800m of beach and a section of kanuka scrub, a spokesman said.
Tenders for the sale close on February 16.