That would mean the trail could still be promoted as a coast-to-coast ride.
Simm, however, said the proposal was "ridiculous".
"We're not prepared to let people go on the alternative route. We consider it to be dangerous and inappropriate for most of the clientele that we've got, who are often on e-bikes and not overly experienced cyclists. We've got a large market share of tourists paying to cycle on this trail so we have to look after their health and safety."
Simm said instead of spending $1.5m on a temporary detour, the council could use the money to find a way of building the trail alongside the railway line.
If that was too difficult, another possibility was to spend the money upgrading the existing walkway between Ōkiato and Russell to make a joint cycling and walking trail.
That way riders using the Twin Coast Cycle Trail would still lose part of the trail from Taumarere to Ōpua, but they would gain a new section of cycleway from the ferry landing at Ōkiato to Russell.
Simm said he was working with the railway trust to allow clients to take a train along the closed section of the trail.
"We might have to suck it up that we can't ride all the way to Ōpua, but have to go on the steam train for part of it. But, in return for that, if the council agreed to upgrade the track from Ōkiato to Russell, then we'd all get a win ... We've got to make sure cyclists have an experience which they're happy with, but at the same time take them to places where they can stay longer, eat out, pay for accommodation and do some shopping. And if they come right into Russell rather than just to Ōpua that would be a big plus."
In the South Island, cycle trails had transformed once-struggling rural towns. He hoped the same would happen in the Far North.
Work is already under way to create a bike path from Ōkiato to Russell, a distance of about 7km.
The Bay of Islands Walkways Trust, which developed the existing walking trail, is behind the proposal.
Earlier this year, chairman William Fuller said the trust had been negotiating with the Far North District Council and planned to build the cycleway in stages.
The trust had funding for the first stage, which would start as soon as a memorandum of understanding was signed.
The trail was expected to traverse road reserve, Department of Conservation land, council land and private property.