It could pierce a tyre and injure horses' hoofs, a rural Whanganui resident says.
But Whanganui District Council infrastructure manager Mark Hughes said the road metal he objects to is just the usual.
Parihauhau Rd resident Russell Smith is objecting to the metal put on his road and the nearby Old Parapara Rd bordering Lismore Forest. He said the latest lot of fractured stones were too sharp and were a danger.
The Old Parapara Rd was re-metalled in June.
All aggregate is regularly tested, Mr Hughes said, and the council and the Whanganui Roading Alliance haven't had any complaints about the quality.