That influence has caused tension with some in the party.
Former North Shore City mayor Andrew Williams left NZ First after being dropped altogether from the party list before last year's election.
He had publicly complained about his demotion in the draft list from three to 13, and said Tracey Martin was threatened by him.
Ms Martin told the Herald that talk of the "Martin dynasty" was wide of the mark.
"We are not that powerful - contrary to what people think. At the end of the day, Mat is where Mat is because of his skills and what he brings.
"Mat came through the candidates process like everyone else, and was placed on the list by a panel of five people. It takes a majority for where people get to on the list, and my mother and I were the minority."
Anne Martin said Mr Paroro's being part of the extended family had nothing "to do with anything".
"I can't even remember what number he is on the list. All that is speculation and I'm not making any comment at this stage. The board hasn't met, it has not been discussed, and we are focusing on not counting our chickens before they hatch."
The NZ First candidate next in line to enter Parliament if Mr Peters wins the byelection is Invercargill hairdresser Ria Bond.
Ms Bond is now a parliamentary staffer working for two NZ First MPs in Wellington.
If she declines, Mr Paroro, who stood in Hutt South last year, is next on the list.
Mr Paroro could not be reached for comment yesterday, but previously told the Herald he was keen on the seat if Ms Bond ruled it out.
He is a Cook Islander who moved to New Zealand for secondary school in 1978 and owns his own network security business.
The Martin clan
• NZ First deputy leader Tracey Martin is related by marriage to Mataroa Paroro, who could be on his way to Parliament if Winston Peters wins the Northland byelection.
• Mr Paroro is next on the list if Ria Bond declines to become an MP.
• Tracey Martin, a former Rodney Local Board member, entered Parliament after the 2011 election as number two on the NZ First list, behind leader Winston Peters.
• Her mother, Anne Martin, was elected president in October 2013 after serving as party secretary for six years.
• Tracey Martin's sister Kirsty Christison has moved from Warkworth to Wellington to work for the Parliamentary Service, including doing research for her sibling and NZ First MP Fletcher Tabuteau.