Ireland Women vice-captain Kim Garth has signed a two-year deal with Cricket Victoria, taking her out of contention for Ed Joyce's World Cup hopefuls.
All-rounder Garth, who has 114 Ireland caps, had been playing winter cricket in Australia but has now made a permanent move Down Under.
"While I have accepted the offer, it was not an easy decision to make," said the 24-year-old.
"To leave family, friends and the whole Irish cricket community was a very difficult decision and one I did not take lightly.
"However, my ambition has always been to be a full-time professional cricketer and to play at the highest level. A chance like this doesn't present itself too often, so I am keen to seize this opportunity."
Head coach Joyce said: "This is obviously a blow, there is no way around that.
"To lose one of your leading players anytime is a challenge, but I can understand Kim's decision-making and she has been quite open with her ambitions.
"Ambition is a good thing, though – I want our players to be ambitious for Ireland and for their careers.
"However, the reality is that it will take a few years for us to be in a position to offer our women cricketers full-time opportunities. We’re on that road, like we did with the men’s contracts, but I am optimistic we will get there with patience and commitment."
Ireland were due to compete at the postponed ICC World Cup qualifier in July in Sri Lanka, however, the ICC will provide an update on the tournament's status in due course.
Cricket Ireland said they had submitted a 'no objection certificate' to the move and hoped Garth, who has already played three seasons in the Women's Big Bash League, would return to play with Ireland down the line.
"While she will step away from Ireland duty, this does not necessarily close the door on her Irish career, and we hope that we may see her in Irish colours once more at some stage in the future," said performance director Richard Holdsworth.
"The contract agreement has been in the pipeline for a little while now, and we had hoped that Kim would have played for us at the World Cup qualifier before starting with Cricket Victoria. With the postponement of that tournament, the timing will no longer allow this.
"We were delighted last year to introduce our first-ever part-time contracts for six women cricketers, but we have to recognise that we are still in the early stages of professionalising the women's game in Ireland and – like we did with the men’s contracts - it will take time while we build up both the financial offering and volume of cricket."