Former agriculture minister George Eustice has called for new laws prohibiting the killing of hares during breeding season.
The Conservative MP said current laws were "hopelessly outdated" and were resulting in the hare population "plummeting".
Speaking in the House of Commons, Mr Eustice said: "Modernising our rules around hare preservation and, in particular, a closed season on the shooting of hares, remains unfinished business.
"Their population has fallen to an estimated 800,000 today from what was thought to be around four million in the mid to late 19th Century."
Mr Eustice said the government estimates that about 300,000 hares are shot in the UK each year, mostly during February and March.
Coupled with this, he said diseases like the rabbit haemorrhagic disease virus (RHDV2) have seen the "instant die off" of hares.
"As our hare population, what is left of it, faces this threat, it is essential that we act now to reduce the mortality of our hare population and to afford our hares the protection that they deserve," he continued.
Mr Eustice said there were "closed seasons" on animals like ducks, pheasants, deer, and geese to prevent them being killed during their breeding seasons. He argued there needs to be a similar enforced closed season for hares.
He said: "The 1892 Act is hopelessly out of date. It is no longer effective. It is, indeed, no longer even enforced."
Mr Eustice said his proposed Hares Preservation Bill would replace the old system, and would expressly prohibit the "killing or taking" of hares during the breeding season.
The Bill has no set date for its return, and due to a lack of parliamentary time it is unlikely to become law in its current form.