An overnight issue with Suncorp Bank's systems has caused some customer accounts to show incorrect balances, with some reporting they were overdrawn hundreds of dollars.
The Queensland-based bank took to social media this morning to assure customers they were looking into the problem.
This afternoon a spokeswoman said there was an issue overnight that had since been resolved, however many customers complaining online said only some or none of their money had reappeared.
Mango Hill resident Michelle Belanji said she felt physically ill when she received a notification saying her account was $116 overdrawn.
"I thought someone must have hacked my account or something sinister as last night I had about $400 in my account," she said.
"I noticed that there was no transactions to show what happened to the money and it had just vanished."
Ms Belanji said she spent most of the morning waiting for Suncorp to rectify the problem.
She said some of the money reappeared in her account about 1:00pm, but not all of it.
Sunshine Coast woman Amy Kübler found her account overdrawn by $17.
"Some people were saying they were having more than $20 overdrawn," Ms Kubler said.
"It was quickly resolved within 30 minutes. I know a few other accounts have been fixed but some people are still waiting.
"I've been with Suncorp for four years now and this is the first time this has happened."
On Facebook, one man said he had $1,400 missing from his account.
He said the money reappeared hours later.
Twitter user Charlie S was still waiting to hear back from the bank when contact by ABC News.
"All I know is we are mysteriously $80 down in my account with no transaction record," he said.
"My sister-in-law is $50 down in hers — same deal, no transaction history."
@suncorpbank balance showing huge negative amount?! It's time to move to a more reliable bank. Mobile banking also constantly down— Wesley Archbell (@wesleyarchbell) February 19, 2017