"I was a bit suspicious, but I thought whoopie, $6000 is a lot of money and I could help my children out. I was shocked when the Post Office lady told me it was a scam."
Mrs Gore said the scammers were "shrewd" operators - she filed a complaint with police and alerted scam watchdog Netsafe.
While no money was taken from her bank account, she had to pay $30 to get a new licence and has been left badly shaken.
"I felt for my age I was reasonably alert and still can't believe this has happened to me. I feel a loss of dignity that I was fooled so easily. I want to warn other people to be careful when someone rings out of the blue offering a big unexpected windfall."
Her daughter Glenda Gillgren said preying on elderly people was "absolutely despicable".
A Netsafe spokeswoman said IRD scams were common, and often the scammer claimed the victim had been chosen to receive a "grant".
"People should be wary if they receive a random call or email claiming there is a payment waiting and asked to provide personal details, and/or requested to make a payment.
"We recommend that people who have provided security-related information, such as mother's maiden name, and/or former residential address notify their bank immediately."
Inspector Karl Wright-St Clair said people needed to be vigilant about being targeted.
"We recognise that some sectors of our community can be vulnerable to these scams, and ask that you look out for elderly family members and friends and make sure they are aware of these incidents," he said.
An Inland Revenue spokesman said the department would never telephone, email or knock on someone's door regarding a tax refund.
"We take all incidents like this very seriously, and offers our sympathy to the person targeted by this scam," the spokesman said.
Anyone concerned they may have been targeted should call 0800 227 774 or call police on 577 4300