The fallout included the resignation of Auditor-General Martin Matthews, who headed the Transport Ministry at the time and was still full of praise for Harrison, even after he was made aware of the wrongdoing.
A State Services Commission review was launched into the Protected Disclosures Act, and State Services Minister Chris Hipkins said a series of workshops will begin next week.
"It is crucial that employees feel safe to report cases of serious misconduct," Hipkins said.
"Anyone who raises issues of serious misconduct or wrongdoing needs to have faith that their role, reputation, and career development will not be jeopardised when speaking up.
"Getting this right is critical to building public confidence in the integrity of government and business in New Zealand."
Hipkins said recent analysis suggested that the law may not be working as effectively as it could, and lags behind international practice in a number of key areas.
The law aims to protect people who report serious wrongdoing in the workplace, but it requires an employee to first raise their concerns with their employer before they can go to an appropriate authority such as police.
The law does not protect employees who leak confidential information to the press.
The New Zealand public sector ranked ninth out of the 19 groups of public and private sector organisations in a study last year into 699 organisations in Australia and New Zealand.
The study said that out of the 10 public sector jurisdictions, the New Zealand public sector ranked eighth behind seven Australian jurisdictions.
Next week's workshops will be attended by stakeholders in the public and private sectors who have knowledge and experience with the law.
The aim is to gather perspectives on the key issues and challenges and discuss the benefits and risks of different reform choices.
Feedback from the workshops will inform the next step in the process, including the issue of a wider public discussion.