He said that he has decided to take up a new role with USA boxing.

Minister for Public Expenditure Brendan Howlin expressed disappointment at the news.

The fellow Wexford native said it's a huge loss to Ireland.

"I understand money wasn't the factor," he said.

"I understand, after a very long time, that something approaching a decent remuneration package was put in place.

"But there are other issues, I understand, but ones that I'm not au fait with, I wasn't directly involved myself.

"I just want to express my disappointment that terms couldn't be arrived at that would certainly be to the benefit of Ireland, and sport in Ireland and boxing in Ireland."

Here's Billy Walsh's statement in full:

It is with deep regret that I am announcing my resignation, as of today’s date, October 19, 2015, as the Head Coach of the Irish High Performance Unit and senior team.

This morning I forwarded my resignation to the Irish Amateur Boxing Association (IABA) Chief Executive Officer Fergal Carruth.

Over the last five decades I have been immersed in the sport of boxing from boy to man and for club and country. I am hugely grateful for the opportunities that my sport has given me both as a boxer and coach.

Since February of this year I have been engaged in a process with the IABA to secure my future as Head Coach with the High Performance Unit and senior team.

A protracted process that went on for eight months included numerous high level meetings that resulted in various proposals.

In August a fair proposal was developed under the auspices of the Irish Sports Council (ISC) that was acceptable and fair but then not subsequently ratified by IABA.

I was hopeful in recent weeks that a final proposal arising out of an approach in late September by the IABA would lead to a successful conclusion but unfortunately it didn’t.

Regrettably the IABA have not made it possible for me to continue on in the role as Head Coach of the High Performance Unit and senior team.

In starting out on this journey back in 2003 our ambition was centered on building a sustainable system for Irish Boxing and I think we have achieved that.

This has been achieved with the work of many excellent people including our outstanding club coaches who produce the pipeline of talent for us in high performance to work with.

Our high performance coaching team contains some of the finest and hardworking coaches in the world, both those from international shores and homegrown. These coaches are part of the legacy of all the hard work it took to build this system.

Zaur Antia, Jim Moore, Eddie Bolger, Pete Taylor, John Conlan, Billy McClean and Dmytri are well positioned to take my work and the work of the high performance programme forward and lead this senior team into Rio to compete for medals.

I have the utmost faith and belief in them having worked alongside them for many years. I am certain our boxers will go to Rio in fantastic shape, ready to compete with the world’s best as the high performance structures are in place to ensure this.

To Emira who provides all our administration and logistics support and gets the team all over the world with little fuss thank you.

We are moving in to our 14th year together as a team and I can say that while there were many difficult and challenging times, I have never done anything in my professional life more rewarding.

The boxers I have worked with (too many to mention for fear of leaving some out) have inspired and challenged me in equal measure and I salute their efforts, their courage and their amazing performances down through these last 14 years.

I wish to thank them for their trust and support and for allowing me to continue in their corner for every fight they fought on the international stage.

I wish them all every success in their endeavors to qualify and secure Olympic Medals at Rio and nobody will be more delighted to see Irish boxers succeed in Rio than me.

To our outstanding sports science and medicine team of physiotherapists, nutritionist, psychologist, strength conditioner, performance analyst and doctor who for all these years operated and performed below the radar so that we could do what we did above it, thank you. This was always a team effort.

I wish to express my gratitude to the Irish Sports Council for all their support and commitment to the IABA High Performance Programme over the course of the last 14 years and most recently in trying to broker an agreement on this matter.

The Sports Council have supported Irish boxing and worked tirelessly to find a solution.

I am very conscious that the negotiations have dragged on for quite some time, but the time has come, with the Rio Olympics in sight and with no solution possible, to provide certainty to all concerned.

Finally I would like to thank my wife Christine and my family for all their support and patience during this time.

While leaving the Irish Team has been one of the hardest decisions I’ve ever had to make, my sights are now firmly set on my future role with USA Boxing.

It is a huge honor for me as a coach to receive the opportunity work with such an iconic sporting nation that is the USA.

I am greatly looking forward to the opportunities ahead in bringing my expertise and experience to the USA Women’s Team as they prepare for success in Rio and beyond.