Former NZ First MP Brendan Horan is being made to look like a problem gambler following his expulsion from the party's caucus.
Leaked parliamentary phone records show he called a TAB betting number 12 times within four hours, it's been reported.
NZ First leader Winston Peters expelled Mr Horan on Tuesday, telling parliament he had "substantive material" relating to allegations the MP misappropriated money from his mother's bank account before she died in August.
Mr Horan denies doing anything wrong, and on Wednesday had to contend with the leaked phone records.
"This is just a witch hunt, I've been accused of everything," he told the New Zealand Herald.
Mr Horan acknowledged he bet on horses but said his gambling wasn't out of control.
Mr Peters won't release the material he referred to in parliament but says he had "no option" but to expel the MP from caucus.
"If Brendan thinks he's done no wrong, he doesn't know what the word `wrong' means," Mr Peters said in an interview with Radio Live.
Mr Horan was back in parliament on Wednesday as an independent list MP, sorting out a new office with Speaker Lockwood Smith.
Mr Peters says Mr Horan should resign from parliament but other party leaders have concerns about that because they don't know what Mr Peters is claiming the MP has done.
"I'm working on second-hand information," Prime Minister John Key told reporters.
"If he's done nothing wrong then he's got a legitimate reason to be here."
Mr Key says it is up to Mr Peters to prove a case against Mr Horan and explain why he thinks the MP has brought parliament into disrepute.
Labour's deputy leader, Grant Robertson, says Mr Horan was elected on the NZ First ticket and doesn't represent an electorate.
"If they (list MPs) are no longer part of a party it calls into question their credibility and legitimacy as an MP - I don't have an immediate answer to that."