Can I complain to a watchdog about government procurement practices?

You have several avenues. The Ombudsman can investigate complaints about the administrative decisions and conduct of public agencies and councils, including whether they followed their own policies and acted fairly and reasonably. The Office of the Auditor-General has powers to inquire into how public entities have used public resources, including procurement, and can accept complaints about matters of concern. For suspected bribery or corruption, you can report to the Serious Fraud Office or the police, and in the case of cartel conduct to the Commerce Commission. Start by raising your concerns in writing with the agency, giving specific examples and evidence, since many bodies expect you to have used the internal complaints process. Consider protection under the Protected Disclosures (Protection of Whistleblowers) Act 2022 if you are an employee.