A Football Fern has revealed new details of the culture of intimidation that will come under scrutiny as New Zealand Football prepares to launch an investigation into the conduct of coach Andreas Heraf.

Stuff spoke to a current player on the condition of anonymity. She claimed members of the playing squad were told they had to ask for Heraf's permission before they could leave the table at dinner time, and that players were shouted at for passing the ball between defence and midfield or if they passed the ball backwards, because it was deemed too risky, a claim backed up by a second Ferns player.

A different player alleged Heraf, at a camp in Spain earlier this year, told a player he knew her club coach and could have her released from her team if he so chose to. In an interview with Stuff in May, Heraf rejected that specific allegation.

GETTY IMAGES Former captain Abby Erceg has been scathing in her assessment of the Football Ferns' coach.

It is understood the majority of the squad have lost faith in Heraf's direction on the field and his conduct off it - and more players than just former captain Abby Erceg are considering their international futures as a result.

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At least 10 players wrote a formal complaint to NZF, via the players association. NZF confirmed the receipt of the complaints in a statement on Tuesday, but would not discuss any details about what they were.

STUFF Former player Katie Duncan feared other Ferns players would retire if Heraf did not change his approach.

Stuff understands the complaints contain allegations of an unprofessional culture, and bullying, along with deep concerns about the on-field approach as Heraf's tenure reaches boiling point.

NZF said the organisation was reviewing the complaints "as a matter of priority" but declined the opportunity to comment further on Tuesday when Stuff requested to speak with both chief executive Andy Martin and Heraf with regards to the fresh claims.

They will instead issue a statement on Wednesday when they are expected to announce an inquiry has been launched.

NZPFA chief executive Harry Ngata would not discuss details either, but confirmed they were seeking an independent review of the Ferns environment, which was viewed as not being conducive to high performance.

"Pretty extensive" statements from players were gathered over the past week, Ngata said. "They've taken it very seriously and they've shown a huge amount of courage in coming forward as a group and saying look, we need some help here."

Heraf's approach has already resulted in one of the country's best players, 138-cap defender Erceg, retiring from international football for the second time in 15 months. At the time she felt unable to comment as to why, but she eventually spoke out in the wake of what she saw in their game against Japan, where Heraf came under heavy criticism following his team's 3-1 loss after saying they adopted an ultra-defensive approach, as they "could have lost 8-0" had they been more positive, playing a team they "will never have [the] quality to compete with".

PHOTOSPORT Football Ferns coach Andreas Heraf.

"I think Andreas' character and mindset is already on show, and will only continue to be put out there as he spends more time in charge," Erceg previously told Stuff.

"If people are up in arms already then that speaks volumes, I think. I think his comments in the media also show his delusional state of mind regarding the ability of the players and he will take two steps back for every step we've taken forward in the past eight years."

Heraf took charge of the Ferns on an interim basis when they toured Thailand last November, following the resignation of long-standing coach Tony Readings earlier that month. He was then appointed to the role permanently, with a group of senior players said by Martin to have requested it from him.

PHOTOSPORT Footbal Ferns' coach Andreas Heraf talks with Rosie White and Katie Bowen during the Japan friendly.

Although one player expressed their concerns to Stuff following the Spain camp, she was reluctant to go on the record after being reminded by the NZPFA that the new collective bargaining agreement has a provision whereby players can be fined up to $5000 for negative comments which bring NZF into disrepute.

There has been a growing wave of criticism, with former Ferns player Katie Duncan calling for his resignation and Ole Football Academy technical director Declan Edge threatening to withhold players from future New Zealand teams. However, Martin said last week that he was not expecting Heraf to step down from his dual posts, as coach and technical director.

However, it appears likely he will at least need to be stood down during the inquiry, and his long-term future with NZF must be in jeopardy given the gravity of the situation.