"During my time in coaching I've always had a close relationship with the team and I am very pleased to have the opportunity to lead the program during this exciting time."
The 64-year-old's first order of business will be naming the side for the OFC Nations Cup in New Caledonia next month.
It has been a difficult year for the Football Ferns after a tumultuous period that led to a wide-ranging review of NZ Football, ultimately leading to the resignation of former coach Heraf.
Earlier this month, the damning findings of the independent review were released, upholding complaints made by members of the Football Ferns about the organisation's conduct and culture, as well as issues with the leadership of Heraf and former NZF boss Andy Martin.
Interim NZ Football CEO Andrew Pragnell said he is looking forward to this new period for the Ferns led by the experienced Sermanni.
"Tom comes to New Zealand with an incredible amount of experience and we are pleased to have coach of his calibre leading the Ferns as they look to qualify for the FIFA Women's World Cup and compete with the best teams in the world," said Pragnell.
"We completed a rigorous recruitment process and Tom presented a great plan and vision for the Football Ferns. We believe he will do a great job in developing the Ferns over the next nine months and we look forward to seeing what the Ferns can achieve in this period.
"It has obviously been a challenging period for the Football Ferns, but following the release of the Independent Review we are looking forward."
