A new bill to protect whistleblowers has been signed into law by President Michael D Higgins.

The Protected Disclosures Bill was passed by the Oireachtas last week and expands an existing law to include protections for volunteers, shareholders, board members and job applicants.

The new law also requires private sector organisations with 50 or more employees to establish formal channels and procedures for their staff to make protected disclosures, as is currently the case in the public sector.

This will be monitored and enforced by the Workplace Relations Commission.

A new Office of the Protected Disclosures Commissioner will be established in the Office of the Ombudsman to support the operation of the new legislation.

The commissioner will direct protected disclosures to the most appropriate body when it is unclear which body is responsible.

Protections for workers will be strengthened through reversal of the burden of proof in civil proceedings concerning allegations of retaliation against whistleblowers.

Minister for Public Expenditure and Reform Michael McGrath said the new law fulfils a commitment to update and reform the Protected Disclosures Act in light of an EU Directive.

"The bill is just one of a suite of measures I am bringing forward in this area," Mr McGrath said.

"We are also overhauling the legislation in the areas of lobbying and ethics and we will see significant progress in these areas after the summer recess."

The new Office of the Protected Disclosures Commissioner will be established and will commence operations later this year.