Paula Bennett thinks Winston Peters needs to "lighten up" and "get a sense of humour" after he rebuked a bunch of flowers she sent him while in hospital.
Bennett, National's deputy leader, told Magic Talk the pair have a "pretty cordial and polite" relationship, but she feels Peters is holding onto grudges from "decades ago".
"He seems to be able to harbour grudges... against the National Party from decades ago. He's all good to dish it out, but if there's something he considers a slight... boy does he react."
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She seemed to be referring to bad blood between Peters and the National Party, some of which dates back to the 1990s, and her own more recent feud with Peters.
Peters was sacked from Cabinet in 1991 under former Prime Minister Jim Bolger's government, after Peters - then a National Party minister - criticised some of the party leadership's policies.
Peters was axed from Cabinet again in 1998 under former Prime Minister Jenny Shipley's government, only that time Peters wasn't a National MP - his NZ First party was in a coalition with National.
Peters hasn't formed a coalition with National ever since, instead forming a confidence and supply arrangement with Labour in 2005, and a coalition agreement with Labour in 2017.
Bennett's feud with Peters reached its peak in 2017 when he admitted having to pay back about $20,000 in pension overpayments he had been receiving since 2010.
Peters took legal action over the leaked information, including against two former National Party ministers Anne Tolley, Social Development Minister at the time, and Bennett who was Minister of State Services.
Bennett and Tolley were advised of the overpayments, but both have denied leaking the information.
"I categorically deny having done it," Bennett told Magic Talk.
But it appears Peters isn't convinced. Newstalk ZB reported last month that he was prepared to settle out of court if Bennett resigned from Parliament.
Bennett said she doubts that was agreed upon. But she said the "fact he's tried to get that up as a media story is slightly entertaining in itself".
When Peters was recovering from surgery last month Bennett had flowers delivered to him, but Peters rejected the bouquet in a public outburst on Twitter.
He characterised it as "seriously bad taste" and admitted to giving them away to an elderly patient.
Bennett said Peters should be more light-hearted.
"I think he needs to get a bit of a sense of humour. I think he gives me more thought than I give him, I've got to say," she told Magic Talk.
Peters said in 2017 his superannuation overpayment might have begun "with an IRD matter which was not picked up", and he was adamant he never lied about his living situation.
Bennett suggested Peters had been inconsistent with his blaming over the situation.
"He's had about 15 different theories over the last couple of years about what happened, verging from the public service through to one of us through to someone in his own camp," she said.
"I've been straight-up, I didn't leak it, I don't know who leaked it, I didn't leak it to someone else to leak it, and I've been absolutely clear on that.
"I imagine there are people within his own organisation and party that knew. I think we're well into being a few dozen people.
"To pick just two of us out, myself and Anne, both of us have been upfront about the fact that we knew and were told; it's drawing dots that really aren't there."
Bennett said she thinks Peters is "a little bit worried about me and my new role".
National announced last month Bennett would not to run for re-election in her Upper Harbour seat in 2020, and would instead take up the position of National Party campaign chair.
Peters described the move as "amateur hour" and questioned Bennett's qualifications.