on (one's) hammer

Primarily heard in Australia.

1. Lecturing or reprimanding one in an annoying, pestering manner, especially about something one considers minor, trivial, or inconsequential; nagging someone. Why are you always on my hammer about this? I told you, I'll do the dishes later! Look, I don't like having to be on your hammer about this, but those reports really need to be filed today.

2. Closely monitoring one. A: "I don't trust Paula, so you need to be on her hammer and then report back to me." B: "Are you serious right now?"