Charities have been urged to comply with their legal requirements in order to boost overall public confidence in the sector.
The Charities Regulator's latest Annual Report shows that 64% of registered charities filed their annual reports on time last year compared to 78% in 2020.
Annual reports provide an overview of charities' finances and activities in the previous year and must be filed within ten months of the charity’s financial year-end.
They are then published on the public Register of Charities.
The Chief Executive of the Charities Regulator has described the decline in the number of charities filing annual reports within the required timeframe as "disappointing".
Helen Martin said it remained a concern, particularly given that research showed reporting requirements were not considered to be unduly onerous by the charity sector.
The Regulator says its registration and compliance units are assessing why some charities are failing to meet this statutory requirement with a view to addressing any underlying issues and encouraging increased compliance in 2022.
The report shows that 282 new charities were registered last year, including 98 schools, bringing the total number of registered charities to 11,426.
The Annual Report also shows that almost half of Irish charities have an annual income of less than €250,000, according to information supplied in annual returns for 2020.
15% of Irish charities have an annual income of more than €1 million.
There was an increase of 22% in the number of concerns raised by the public - up from 466 in 2020 to 568 in 2021.
Ms Martin said the increase was not unexpected given the gradual resumption of activity by charities during the year, as public health restrictions eased, along with increased public awareness of charity regulation due to the significant role played by many registered charities during the pandemic.
While concerns relating to unregistered organisations remain high, governance and issues linked to financial control and transparency within registered charities continued to generate the most concerns among the public.
37% of concerns related to governance, 35% related to the legitimacy of charity, financial control and transparency concerns stood at 19%
The top five sectors in which Ireland’s registered charities operated were: the advancement of education (5,982); community welfare (2,150); integration into society of those who are disadvantaged (1,570); relief of poverty or economic hardship (1,331) and community development (1,294).
Dublin has the highest number of registered charities at 3,140, followed by Cork with 1,177 and Galway with 661.
Eight protected disclosures were submitted to the Regulator last year and two statutory investigations were opened in relation to North Inner City Homeless and Birdwatch Ireland.
Two investigation reports were published, relating to Childfund Ireland and Cabhrú Housing Association Services.