The deadline for designs for a possible new flag was midnight on Thursday.
Flag Consideration Panel chairman Professor John Burrows thanked those who had submitted designs.
"As expected, there are hundreds of designs that have come in just ahead of the deadline and these will need to go through the same robust checking process as others to ensure they meet the guidelines and terms and conditions," Professor Burrows said.
The final count would be completed within two days, and the final number could hit 10,000.
"The panel will then look at how the designs suggested bring together values and our identity as a nation," Professor Burrows said.
"There are also a large number of other factors we need to consider in this rigorous process from a practical and technical perspective, to ensure designs would be workable and 'fit for purpose', as well as meeting the principles of good flag design."
Professor Burrows said that designs received to date had featured predominant colours such as white, blue and red and symbols and themes including the Southern Cross, koru, fern and Maori culture.
"The panel will announce the preliminary long list of between 50 to 75 designs by mid-August and the four alternatives that the public will rank in the first referendum will be announced by mid-September," he said.
The process for the flag referendums has been criticised after a low turnout to public meetings. The first referendum is expected to be held in November and December and will ask voters to rank their preferences from a shortlist of four designs the panel picks.
Flag designs can be viewed on www.flag.govt.nz.
