Phena was admitted as a Solicitor in the Republic of Ireland in June 1996.  She completed her three years training and then continued to work as a Solicitor with Garrett Sheehan & Company Solicitors in Dublin until 2004.  During that time she worked almost exclusively as a criminal practitioner appearing in the Irish District Court and instructing Counsel in the Irish Circuit Court, Central Criminal Court, Special Criminal Court, Court of Criminal Appeal and Supreme Court.

Phena was responsible for the running and co-ordination of the Central Criminal Court and High Court Judicial Review section of Garrett Sheehan & Company from 1999 to 2004.  Most of her work in recent years was on high profile murder cases and cases of serious sexual offences.  She also has experience of Extradition and Mental Health cases in Ireland.

Phena left Ireland in 2004 originally to live in Australia, but has now made the move to Queenstown.  She joined MACTODD in August 2005 as a Criminal Litigator and was admitted as a Barrister & Solicitor in New Zealand in July 2006.