Since he was contacted by NZME News Service yesterday, donations have jumped from $8000 to almost $9500 by 11am today.
"You (sic) criminal past does not mean we can't show some compassion here. Wishing you all the very best for you and your family," one generous donor wrote on his page this morning.
"No stones to cast, only love," another posted.
In the last few days, some people had questioned the validity of Mr Mitchell's cancer claims, given his fraudulent history.
Givealittle investigated after receiving a report from a member of the public questioning Mr Mitchell's claims.
The fundraising platform asked Mr Mitchell for "additional information and evidence".
"As a result we are satisfied that the Givealittle page reflects the situation facing Mr Allan Mitchell, though we acknowledge that we are unable to verify specific allegations about his past or character, and therefore not able to restrict access to the platform on this basis," a spokeswoman said.
"The page is open for donations and the investigation has concluded."
Givealittle also confirmed the verified payee for the Givealittle page had been updated from Mr Mitchell to Braemar Hospital and all funds would be paid from the Givealittle Trust account to Braemar Hospital.
"We are confident that this case is a clear demonstration that Givealittle processes work effectively to protect donor trust and confidence," they said in a statement.
NZME News Service has seen a letter from Mr Mitchell's radiation oncologist that appears to validate his claims.
The oncologist yesterday refused to discuss his case, citing patient confidentiality.
Mr Mitchell told NZME News Service that he has nothing to hide.
"It was way way way in my past," he said.
"And it wasn't bad frauds, it was just little things that happened because of circumstances.
"There's things in my past I can't help, all a long time ago, and if that causes this not to work... well, I am coming to peace with whatever happens."
Mr Mitchell has the close support of his girlfriend, and two children Alicia, 23, and 20-year-old son, Luke.
With his speech deteriorating, he started radiation therapy last week. He is also trying intravenous vitamin C injections, at a cost of $20,000, which are designed to slow down the cancerous growths.
But his main hopes lie in the new drug, Pembrolizumab.
"Hopefully I will last this long," he wrote on his Givealittle page.
Son Luke was touched by the support shown for his "ticking time bomb" Dad.
"It is incredible to see people band together to help a fellow New Zealander," he said.
Pembrolizumab is a "scary but very exciting" prospect, Mr Mitchell said.
But it's the only option he has.
"I either fade away and die or do my best to get on the programme that will probably give me some more life."
Givealittle's core process includes:
• Donor validation: a system requirement of three independent donors before a page shows in the Givealittle search, explore or home page or without a donor warning
• Payee verification: identity and bank account verification of all payees of funds raised on Givealittle
• Givealittle has a strong self regulating design and encourage the public to report concerns or information outside of that represented on a Givealittle page. A public report triggers a complaints and investigation process.
• Givealittle does not require standard disclosure of criminal convictions of page owners or payees, however if they are notified of actual or alleged criminal history through our public reporting process they verify this through the investigation process. This may include undertaking a police check.
• Givealittle does not require evidence of need, however they routinely request further information as part of the moderation process as part of an internal red flags process and where are page is reported by a member of the public on the basis of misrepresentation, our investigation will seek appropriate evidence.
