The Financial Services Union (FSU) has described as "unacceptably high" the gender pay gap reported across the banking sector.

Under new laws, companies with more than 250 staff must report their gender pay gaps in the month of December.

Each of the four main retail banks have now reported their findings, with the mean gender pay gap averaging 21.1% across the four main banks and the median averaging 16.96%.

"The numbers reported across all the retail banks are very worrying and deserving of urgent attention," said John O'Connell, General Secretary of the FSU.

"The gender pay gap can best be resolved through a willingness of employers to engage with unions and agree action plans that put this issue as a core objective of their business plan," Mr O'Connell said.

The FSU is calling for a range of measures, including greater transparency around pay ranges, more part-time and flexible working arrangements for staff and audits of pay increases to ensure fairness and equality.

Organisations across Ireland have been reporting their gender pay gaps throughout December.

On Monday, RTÉ reported a median gender pay gap of 13.03% in favour of men, which reduces to 6.79% when roles with overtime are excluded.

The broadcaster said it has a mean, or average, gender pay gap of 11.55% which reduces to 10% when roles with overtime are excluded.

Dublin City Council has a mean gender pay gap of 4.8%, the ESB reported an average gender pay gap of 10.9%, while An Post recently reported a zero gender pay gap for the second year in a row.

The national gender pay gap in Ireland is estimated to be 11.3%, according to Eurostat figures from 2019, compared to an EU average of 13%.