Nearly 60 per cent of local authorities slashed drug and alcohol treatment budgets for adults last year - moves described as a "false economy" by a cross-party group of MPs.
The all-party parliamentary group (APPG) on children of alcoholics is calling for ministers to reverse cuts to local authority funding after collecting the concerning freedom of information (FOI) data from councils.
According to the FOI data, last year councils cut treatment services by four per cent nationwide, while hospitals have seen increasing admissions for alcohol-related conditions for nearly a decade.
Councils reported a projected spend of £507m for 2018/19, down from £526m in 2017/18.
Four local authorities admitted reducing budgets by £1.5m each, while 16 trimmed £500,000 from services.
In 2008/09, there were 296,197 drug and alcohol-related admissions, rising by 39,018 in 2017/18 to 335,215.
By contrast, councils reported a seven per cent drop in the number of referrals to alcohol treatment services last year, suggesting that patients are receiving urgent help because they are not supported earlier.
Responses suggest councils plan a further two per cent cut on average next year.
Group chair Liam Byrne, whose father died from alcoholism in 2015, said that the government was spending on accident and emergency admissions when it should be "trying to tackle the addiction that lands people in hospital in the first place".
Byrne added: "Every child of an alcoholic comes to learn the brutal hard way that we can't change things for our parents - but we can change things for our children.
"Frankly that's harder if addiction treatment budgets are being cut left, right and centre.
"What this year's data shows is that it's simply a false economy."
In December last year, the government confirmed a cut to councils' public health grants of £531m between 2015/16 and 2019/20.
The announcement followed research published by the Health Foundation that showed an additional £3.2bn a year was required to reverse the impact of government cuts to the public health grant.
The average budget cut next year is expected to be £75,000, with 93 per cent of local authorities reporting that addiction treatment budgets will stand still or fall next year.
Another APPG member, shadow health secretary Jonathan Ashworth, said the "deep cuts" were failing "some of the most vulnerable in society".
He added: "Government ministers must reverse these cuts as a matter of urgency."
Despite the otherwise bleak picture, 67 per cent of councils said they have some form of strategy in place to support children of alcoholics.
This compares to less than 50 per cent last year, and less than 25 per cent in 2015.
In December last year, the government announced nine councils would receive £4.5m to support children of alcoholic and drink-dependent parents.
The National Association for Children of Alcoholics (Nacoa) estimates 2.6 million children in the UK are living with an alcohol-dependent parent.
With the APPG, Nacoa is hosting a lecture in the House of Commons to mark Children of Alcoholics week on 14 February 2018.
A Department of Health and Social Care spokesperson said: "All children deserve a stable and happy place to call home and it's heart-breaking that hundreds of thousands of children growing up with alcohol-addicted parents in this country are robbed of this.
"Children whose parents are dependent on alcohol face a poorer outlook in all aspects of their life - from their education to their mental health.
"In December we committed to fund the National Association for the Children of Alcoholics' helpline expansion, so that more children in this difficult position have rapid access to support and advice."