Just after 8am the A4 drawing had reached $19,338.
All proceeds of the TVNZ auction will go to the Cure Kids charity.
Mr Key draw the silver fern on TVNZ's Breakfast programme at presenter Pippa Wetzell's request.
The prime minister said, in response to the New Zealand Herald's newspaper campaign, that changing the New Zealand flag was not on the agenda, but if it was to change his preference would be the silver fern.
Mr Key will meet the winner of the auction for morning tea.
There are hundreds of comments on the auction including about how the fern picture looks more like a Christmas tree, whether GST would be added to the price and whether Ms Wetzell was single and also available for morning tea.
