The Cancer Society is warning against scammers after an elderly woman was asked for her bank details over the phone by someone claiming to be from the charity.

Jan Robinson, who is applying to become a volunteer driver for the Cancer Society in the Manawatu, received a phone call on Tuesday afternoon by a woman pitching a donation plan of $4 a week.

"She started by thanking me for my previous donations to the Cancer Society and then was very aggressive, wanting bank account details from me for an automatic payment," Robinson said.

"I said 'I don't give bank details over the phone' but she wouldn't take no for an answer."

Robinson refused to give her bank details and hung up on the scammer after she pushed for credit card details.

"She's very good at it, I must admit," Robinson said.

"It felt like she'd been in that line of work for a while."

Robinson reported the call to the police and the Cancer Society.

Police said they had had no other reports but anyone who received a similar call should contact them, or Netsafe on 0508 638 723.

Acting chief executive of the Cancer Society's central districts division, Chris Franklyn, said fraud attempts like this were "incredibly annoying and disheartening" but he was glad no money was handed over.

"When scammers use our name to target fake donations, they are actually stealing money from people with cancer.

"We do not receive any government funding and people generously donate that money to support patients with cancer and fund research and the services we offer and that's where they expect to see that money used."