The Competition and Markets Authority (CMA) said it had “serious concerns” after interim findings of its inquiry launched six months ago uncovered above-inflation price rises for funeral director and crematoria services.
It found the price of the essential elements of a funeral had increased by more than two thirds in the past ten years, almost three times the rate of inflation.
Costs for cremations, which now account for 77 per cent of all funerals, have rocketed by 84 per cent on average, it added.
The CMA said it believed the full powers of a major market investigation were now needed, given the scale of the issues uncovered.
It said: “Initial work indicates problems with the market that have led to above-inflation price rises for well over a decade, both for funeral director services and crematoria services.
“The scale of these price rises does not currently appear to be justified by cost increases or quality improvements.”
Shares in listed funerals firm Dignity plunged 16 per cent after the CMA announcement.
It comes as the UK Government is also planning a crackdown on so-called rip-off pre-paid funeral plan providers who prey on the vulnerable.
The Treasury is proposing bringing the sector under the regulation of the Financial Conduct Authority after evidence showed elderly people are being “pressured, harassed and misled” by some operators.
CMA chief executive Andrea Coscelli said: “People mourning the loss of a loved one are extremely vulnerable and at risk of being exploited.
“We need to make sure that they are protected at such an emotional time and we’re very concerned about the substantial increases in funeral prices over the past decade.
“We now feel that the full powers of a market investigation are required to address the issues we have found.”
The CMA’s research so far has shown that people generally spend £3,000 to £5,000 organising a funeral.
This would now represent nearly 40 per cent of annual outgoings for those on the lowest income - more than they spend on food, clothing and energy combined.
It also found that customers can save more than £1,000 by looking at a range of choices in their local area, although many are in distress and unable to do this, leaving them vulnerable to high prices.
The CMA wants to hear from people who have experienced poor practices in the sector and wider industry views on the issues it has identified by 4 January.
Ian Strang, co-founder of funeral comparison site Beyond, said: “It is a clear indication of how the UK’s funeral sector has been allowed to become like the Wild West.”
Pippa Wicks, deputy chief executive for the Co-operative, said: “Over the last three years we have started to tackle funeral affordability by reducing prices on our most affordable funerals and introducing new choices for our clients.
“Through this period we have seen an increasing number of families choosing lower-cost options and we are committed to continuing to provide even more affordable choices.
“However, we recognise that there is still more to do and we welcome any measures from the CMA that will protect families and ensure that they have access to high standards of funeral care at an affordable price.”