Horse riders, motorists and local MPs have highlighted the “immense risk” of mass cycle rides ahead of the Wiggle New Forest Sportive this weekend.

More than 4,000 cyclists are expected to descend on Brockenhurst in the New Forest National Park to attempt routes of either 58 or 86 miles.

But horse owners say the event will create “no-go zones” for other forest users.

Dr Julian Lewis, New Forest East MP, has written to transport minister Norman Baker calling for such events to be subject to the same formal licensing regulations as road races and time trial events.

The Tory MP said: "We should not wait for a serious incident before deciding upon an appropriate degree of regulation - not something heavy handed but something recognising that both the frequency and size of these huge commercial cycling events have greatly increased."

“Events of this size on public roads clearly need some form of regulation and/or licensing.”

The letter accuses riders of flouting the Highway Code and refers to two near misses involving cyclists and forest animals.

Dr Tony Hockley, of the New Forest Equestrian Association (NFEA), said there was "immense risk" to horses and riders because of the numbers of cyclists.

He told the BBC: "I'm not against cyclists, I'm a keen cyclist myself but it's just the sheer scale of these new phenomena as parts of the forest become no-go zones."

UK Cycling Events have said commercially-run rides such as the Wiggle New Forest Sportive are safe, environmentally friendly and give a boost to the local economy.

The business, which has organised the event for the past five years, also said it had benefited from the legacy of British cycling success at the 2012 Olympics and Tour de France.

Martin Barden of Fordingbridge-based UK Cycling Events, dismissed the criticism as “baffling” and insisted the event is a "benchmark of safety" with safety briefings, first aid points and support vehicles.

Mr Barden said: "It's just a great family day out with all ages wanting to enjoy the New Forest and get fit in a way that isn't damaging to the environment. Any cyclist seen to be breaking the Highway Code will, as part of our terms and conditions, be banned from future events.”

“In very difficult economic times, it is a boost to local businesses - people stay in local accommodation, they buy supplies in local shops and local businesses supply our on-site catering."

Richard Senior, owner of tourism guide, iNewForest.com said events such as the spring sportive are the "lifeblood for tourism businesses".