The submissions process closes on April 23, coinciding with the centenary of the Anzac landing. He says that distracts from the occasion and disrespects those who served. "The fact submissions close two days before Anzac Day is quite gross," Mr Hill said.
"A hundred years ago, our young people went away to war and lost their lives. This has gone ahead with no consideration of our past, and the sacrifices made under that flag.
"It's disgraceful."
With the bill before Parliament, Mr Hill hoped RSA members would air their concerns about the referendum and its $26 million price tag.
As set out by the bill, a government-appointed committee of prominent New Zealanders, such as Sir Brian Lochore and Beatrice Faumuina, will choose the design of four alternative flags from which New Zealanders will select one.
That preference will then be pitted against the existing flag for the public to vote on in a second referendum.
Mr Hill questioned the need for the lengthy process when the public had not demanded change, calling it "a one-person crusade".
"Where are all the people marching on Parliament clamouring for a new flag?
"Why not simply ask people if they want a new flag, yes or no?
"By bringing in those other designs, they are trying to manipulate the outcome."
As for the money spent, it could have "endless" other uses.
"It could be spent on youth and education.
"Or think of all the cataract operations and hip replacements it could pay for."
Mr Hill said the flag had personal significance for him. He served in Southeast Asia, and his uncles fought and died in both world wars.
"The flag represents the present and the past - the [Union Jack] reminds us of our past and the stars remind us of where we should go in the future."
The RSA has a page titled "Fight for Our Flag" on its website, with instructions for those wanting to make a submission to Parliament.
-For more information, go to www.rsa.org.nz/Community/FightforOurFlag.