Ireland is set to miss a deadline to hire managers for Apple's tax billions during an appeal of a European Union competition ruling, according to reports from financial news service Bloomberg.

This marks the latest delay in a saga that has dragged on for more than a year, the news agency said.

The National Treasury Management Agency is hiring custodians and investment managers for the estimated €13 billion in back taxes Ireland has been ordered to collect from the iPhone maker.

It had planned to award contracts by the midlde of November, according to tender documents it issued in July and September.

As of today, no one has been hired, Bloomberg said.

The processes are ongoing and the timetables in the tender documents were only for guidance, a spokesman for the agency said in an email response to questions.

In an order that reverberated across the Atlantic, the European Commission last year slapped Apple with a tax bill of as much as €13 billion, saying Ireland granted unfair deals that reduced the company's effective corporate tax rate.

The Commission sued Ireland in October for failing to collect the taxes quickly enough.

The final figure could be about €14 billion, including interest, Apple said earlier this month.

While Apple and Ireland appeal the EU decision, regulators had demanded that Ireland hold the money in escrow until the process is complete.