Mr Fraser said the trust's objective had been to develop a high-standard network of trails and pathways long the rivers in Waipawa and Waipukurau for locals, and to attract people from outside the district.
Coupled with the work the trust and others had done in developing the Gum Tree Mountain Bike Park in Waipukurau and fundraising for an 84m swingbridge across the Tukituki River to link the limestone pathways in the towns, the trust was "as good as there" in achieving its objective.
"What a shame if a few locals continue to undo all the progress we have made. It is time we get all the interested parties together and set the rules as to how we use the river for recreation."
Waipawa horse rider Alison Stoelwinder accused Mr Fraser of doing a backflip.
She said he had been quoted as far back as 2013 as saying the berm trails and Rotary pathways were open to all recreational users, including horse riders.
"He's just using this latest incident as an excuse to have a go at us horse riders," said Mrs Stoelwinder, who moved to CHB from England more than 10 years ago.
"He says he wants to attract people here. I came to CHB specifically for this reason [to ride horses] and have ridden beside the river ever since."
Mrs Stoelwinder pointed out the river berm trails and Rotary pathways were on public land owned by the Hawke's Bay Regional Council (HBRC) and vowed to keep riding there even after "being abused" by mountain bikers more than once.
She said she did ride on the Rotary pathways, when the berm trails were too "trashed" by motor vehicles to be safe for horse riding, having had her horse slip and fall on her while tackling a muddied trail last winter.
Her horses wore no shoes, and she always cleaned up after them.
"You can see the damage where vehicles have driven, but you can't see where I've ridden," she said.
HBRC's engineering officer for rivers, Vince Byrne, said damage caused to pathways and river reserves, mainly from vehicles and motorbikes, was not confined to CHB and was worse in Napier and Hastings.
Anyone caught driving vehicles on the stopbanks or limestone pathways could be prosecuted, and the council had limited vehicle access in many areas.
"But we don't want to close everything off, as it would preclude everybody. I am not sure what the answer is," he said.