A West Midlands MP who used to make her living writing wills has warned the industry attracts "the incompetent, the dishonest and the fly-by-night operator".
Lorely Burt (Lib Dem Solihull) called for tight regulations to prevent people setting themselves up as professional will writers without proper training.
But she admitted she had drafted wills for customers despite having no legal qualifications, before she became an MP in 2005.
Ms Burt said she had received training from a private company, and the wills she helped draw up were sent to legal professionals to be checked.
However, she warned many willwriters
acted had no training at all. She added: "Many consumers do not appreciate the difference between a will writer and a solicitor.
"In fact, many assume that a will, being a legal document, can be drafted only by a solicitor."
Ms Burt, leading a Commons debate on the will writing industry, said the law used to be that only solicitors could draft wills but this changed in 1980.
She said: "In the years between being selected to fight and winning my seat, to earn money in a flexible way that could fit in with campaigning, I worked as a part-time, self-employed will writer with a company called, strangely enough, the Will Writing Company, which did what it said on the tin. I was not legally trained, but I was trained by the company and sat exams set by the Institute of Professional Willwriters, which were marked externally."
She warned MPs: "Independent financial advisers are regulated and required to be qualified, and solicitors need to be qualified and closely controlled, but someone could be a convicted fraudster, set up as a will writer tomorrow with no qualifications, experience or professional indemnity insurance and proceed to dispense advice.
"Most consumers are unable to judge the quality or value of the service that they are getting, so it is no exaggeration to say that will writing has become a happy hunting ground for the incompetent, the dishonest and the fly-by-night operator."
Most customers never knew if their will had been badly written, as problems only emerged after they died.
She warned: "Will writers do not need to be legally qualified as long as they are properly trained, but as things stand, customers are sitting ducks."
However, Justice Minister Bridget Prentice said the Government had no plans to change the law.
She said: "The crux of the matter is whether will writing should be a reserved legal activity."