The average cost of dying has risen to £7,248, according to a survey which warns that many bereaved families will struggle to cover all the expenses.

The analysis of death-related costs from insurance company Sun Life Direct, which include funerals, probate costs and memorials such as headstones, shows that next of kin and other key relatives are often ill-prepared to cover the final bills.

More than a quarter (26%) of participants in the survey admitted they had made no plans for the practicalities of later life, while 87% had made no arrangements regarding where they will live and how they will be cared for if they are unable to look after themselves in old age.

The research shows that in the UK today, end-of-life costs have increased to an average of £7,248 – a rise of 20% since 2007 and more than £400 since 2010.

Specifically, funeral costs have increased by 61% over the past seven years, which Sun Life Direct believes will continue for the foreseeable future. The report also reveals that this increase in costs has been met with surprise and concern from those who have responsibility for such arrangements.

Simon Cox, head of life planning at Sun Life Direct, said: "Many people are sleepwalking into a financial nightmare, leaving end-of-life plans to their families, the state or no one at all.

"As a nation we need a wake-up call. Our research indicates that although there is indeed openness to talking about death, action is still greatly lacking. Steps need to be taken to avert the sort of distress and concern experienced by the nearly one-in-five (100,000) people who struggle with funeral costs."

Dr Kate Woodthorpe, a lecturer in sociology at the University of Bath, said the number of deaths in England and Wales was at an all-time low, but was set to rise significantly. While 491,348 deaths were registered in 2009, she said that by 2030 an additional 80,000 people would die each year.

"As a society, we have to ask ourselves whether the current infrastructure for end-of-life support is fit for purpose," she said.

Meanwhile, separate research revealed that families are holding on to their loved ones' ashes after death because of restrictions and confusion on scattering cremated remains.

The study by the Co-operative Funeralcare, which has 880 funeral homes nationwide, revealed that three in five people would like to scatter a relative's ashes at a special place or bury them under a memorial, but were prevented from doing so because of rules or environmental concerns.

It said three out of four people were keeping ashes for up to a year. The most popular place to keep them was on the mantelpiece, but more than a fifth would choose the bedroom while one in 17 would store them in the attic, bathroom or garage.