I don't think it's K. elatine. (a) none of the leaves are hastate/sagitate/lobed (b) The pedicels are hairy. This picture looks much more like K. spuria. (as do others on CNM)
Not aware of any records from the ACT of K. spuria. So would be worth making a specimen perhaps and confirming the ID as it would be an interesting find
I am still inclined to think our records as K. elatineon as some of the leaves are hastate and the sepals are pretty spaced and smallish so hard to see them overlapping the fruit - but I could be wrong.