Was hired as a temporary employee (not through an agency) for one year and was told by HR that maybe after 6 months they would consider bringing me on FT. Would it be better to express my interest with HR instead of my manager since they were the ones who originally mentioned it?
If you didn’t get that promise from HR in writing, it didn’t happen.
In some countries there are labour laws that determine that you have to become permanent if you have worked in the same role for a period.
HR is the company’s department that manages its human assets, you.
Your manager is the person who determines if you’re useful and will instruct HR accordingly.
The only time you’d go to HR directly is if your manager is dysfunctional or if they were advertising a new position you want to apply for.