New Zealand Football confirm Football Ferns players have penned letters of complaint about coach Andreas Heraf

New Zealand Football have confirmed a Herald report that Football Ferns players have filed complaints about coach Andreas Heraf.

Major issues have developed between the players and Heraf, with significant concerns around the culture and environment. The Herald understands at least a staggering 10 players in the squad have written formal letters of complaint about Heraf's conduct.

One or two would be enough to raise eyebrows - and serious doubts - but that number represents at least half the squad.

The New Zealand Football board were discussing the latest developments around Heraf last night.

NZF released a statment today saying it has "received a letter from the NZ Professional Footballers Association (NZPFA) last night with a number of complaints from the players of the Football Ferns".

New Zealand Football said they are reviewing the complaints as a matter of priority and will release a further statement tomorrow.

The players' correspondence is believed to be related to incidents from the recent week in camp for the clash with Japan in Wellington and also the tour to Spain in March, when New Zealand faced Scotland in two friendly matches.

The situation is in direct contrast to the picture painted by NZF chief executive Andy Martin last week.

When responding to the fallout from the Japan game and Heraf's controversial post-game statements, Martin, while admitting some of Heraf's comments were "strange", endorsed the Austrian as the right man for the job.

"We have someone with real capability and he has to perform," said Martin. "Our job is to support him and give him every opportunity."

Martin also seemed to dismiss any possibility of wider issues or problems, saying: "Let's keep things in context - we lost a game of football."

He also denied there were any issues between Heraf and the playing group, saying concerns raised by former Ferns Abby Erceg and Katie Duncan were relevant only to them.

The written protests, believed to be unprecedented in New Zealand Football history, is a brave step by the players.

It's one thing to have a quiet word to a friend or mentor, or seek a meeting with a player's representative or the like but it's completely another to put it down on paper.

With the Women's World Cup less than 12 months away, they will know it could have repercussions for their international futures, especially if Heraf remains in charge.

Even if he steps away from the Ferns role, Heraf is also NZF technical director, which gives him overarching responsibility across all national teams.

It's also a courageous move given recent events. When allegations of problems with the team environment first surfaced after the Spain tour, they were quickly shut down by NZF.

One player spoke to another New Zealand media organisation but was then essentially put under a gagging order by NZF under the terms of the new collective agreement.

The players were reluctant to speak out last week but may now feel a drastic step is needed.

There is believed to be frustration among players that a report written by an NZF staff member outlining concerns with the culture and environment on the tour to Spain in March wasn't acted on by the national body.

Heraf was appointed Ferns coach last December. Although there was an obvious conflict of interest - and it's an arrangement that is rare, if not non-existent across the footballing world - the appointment was rubber-stamped by Martin and the NZF board.

At the time of his appointment, Heraf's coaching career had been almost exclusively limited to male teams.

It's not yet known what action NZF will take but a review or investigation into the allegations raised by the players would seem inevitable, and the spotlight will now go on Heraf and Martin.

Neither were available for comment yesterday.