A man who posed as a cancer patient and scammed millions of dollars from a wealthy woman has been jailed for four years and eight months.

Paul Tuba Mika, 55, told the woman he had lost everything. His wife and son had died, so he was donating his body to science in an experimental cancer treatment.

Mika told the woman he needed money to pay for airfares to Australia and medical bills - and his 78-year-old target gave him $2.4 million over nearly eight years.

His doctor would even call her to give progress reports.

But there was no cancer treatment and no doctor.

Mika was sentenced in the Auckland District Court today on eight charges of obtaining by deception.

Judge Patrick Treston said the victim felt "vulnerable and disillusioned" by Mika's offending.

Judge Treston said there was no chance of reparation payments because Mika claimed to have spent the $2.4m on drinking and gambling.

He said Mika had 23 previous convictions for dishonesty offences and in December 2003 was sentenced on similar offending.

"And what makes it worse for you is that this offending was occurring while you were on bail and serving a sentence for those matters."

Mika's latest victim - who has name suppression to protect her identity - lives in an upmarket Auckland suburb.

Mika met her in 2003 when he was collecting donations for recognised charities.

But in May that year, he asked for money for himself.

He said his wife and son had died, and all he had left was his body, so he planned to participate in experimental cancer testing in Australia.

But he needed money for the costs of the cancer testing, including flights to Australia and medication.

Moved by his plea, the woman wrote a cash cheque for $13,200.

But Mika did not go to Australia and did not take part in any cancer treatment testing.

Instead, he banked the cheque at the Westpac branch in Ponsonby.

For the next seven years, he kept up the charade and continued asking the woman for money.

At times, he would act as though he was extremely ill, and several times the woman received phone calls from a man purporting to be Mika's doctor.

The "doctor" told her Mika was "putting himself through hell" but the cancer testing results were "tremendous".

She gave him 166 cheques between May 2003 and March last year - a total of $2,421,835.

When the fraud was discovered last year, she told police she had no reason not to believe Mika.