Staff costs at the beefed up Data Protection Commission (DPC) last year more than doubled to €7.2m.
This came as the DPC increased the number of people it employs from 90 to 138 at the end of last year.
Numbers employed at the data watchdog have since increased to 146, and, according to a DPC spokesman, that number will increase to 175 by the end of this year with the commission currently recruiting for a number of posts.
The large increase in headcount at the DPC comes against the background of the commission currently conducting 23 big tech inquiries.
Some of the data inquires last year related to the world's largest social media brands including Facebook, WhatsApp and Twitter.
Last year was also the first full year of operation of the General Data Protection Regulation (GDPR).
The DPC opened six statutory inquires into multinational tech firms' compliance with GDPR in 2019. The rise in DPC employment coincided with the number of data complaints received increasing by 75pc to 7,215 with a large percentage of its resources dedicated to investigating individual complaints.
New documents show that the total cost of operating the DPC last year more than doubled from €5.4m to €10.4m that included staff costs increasing from €3.2m to €7.2m.
The DPC's legal costs last year declined from €1.16m to €1.13m and that included legal fees concerning legal proceedings totalling €823,544.
Data Protection Commissioner Helen Dixon was paid €159,725, made up of €141,249 in an annual salary and €18,476 in arrears from July 2017 to July 2019.
Ms Dixon was re-appointed for a second five year term of office last September.
Pay to key management personnel last year totalled €667,353. On the DPC's contingent liabilities, a note attached to the accounts states that the DPC is engaged in a number of cases before the court. The note states that there are a number of cases where costs have been awarded against the DPC, "however, the value of these costs are not known at present". Underlining the DPC's increased workload last year, the number of valid data security breaches notified to the Commission increased by 71pc to 6,069
At the end of last year, the DPC had 70 statutory inquiries on hand, including 49 domestic inquiries. The DPC's rent bill last year totalled €848,182 with equipment maintenance and office supplies costs totalling €529,860.