Horse owners could be saddled with an annual tax of up to £100, according to Chris House, president of the British Equine Veterinary Association (BEVA).
House claims BEVA has estimated administration costs for collecting the tax and figures the government quoted figure of £10.50 per horse is just not enough to maintain the proposed levy.
In March, the Department of Environment and Rural Affairs (Defra) announced plans to delegate looking after animal health in England to a new organisation - and to share the running costs with farming and probably equestrianism.
Defra has put forward £10.50 as the likely annual charge per year for horse owners.
Mr House said BEVA had set-up and collection costs for the levy adding up to a higher cost of the scheme.
Proposal is still speculative
"This was put to a Defra official at a British Veterinary Association (BVA) meeting in Cardiff recently — and he did not deny it," said House.
"This figure is still speculative. There is little detail about how the scheme will work for horses. But if correct, it will have a phenomenal effect on the industry, not least the welfare organisations. The Donkey Sanctuary, for example, owns over 3,000 equines.”
"Defra is working towards publishing legislative proposals in late 2010, with any changes in England not expected before 2012,” said a spokesman.
The Defra committee putting the proposal together meets again on November 4.
How to join the campaign against the tax
If you are a country lover who wants to help the campaign against the horse tax, you can join a petition at Rethink The Horse Tax, which is a group backed by several major equestrian groups.
The campaign claims more than 10 million people who love horse riding or watching equestrian events may be affected by the tax.
The main arguments against the tax are that the equestrian share of the tax is arbitrarily set at 20% o0f the total with no real basis for the figures and that the proposed levy will raise about £4.5 million a year – but will cost £2.43 million a year to administrate and collect, leaving too little in the pot to finance any initiatives.
A point to consider if you are against the tax is that Defra plans to publish their proposals for the tax after the next election, so discussing the standpoint with your local parliamentary candidates at the general election in May or June next year could lead to pressure forcing the government to drop the plan.