The number of family court cases involving contact with children in which neither party are represented by lawyers have nearly doubled in the last year, a report on the impact of legal aid cuts has found.
There were 17,268 cases involving contact with children where both parties represented themselves starting in the family courts in 2013/14, an increase of 8,110 or 89% on the previous year, the National Audit Office (NAO) spending watchdog said.
There were 79,747 cases starting in the family courts where both parties were so-called litigants in person in the year 2013/14, an increase of 18,519 or 30% from the previous year, the NAO added.
The Ministry of Justice (MoJ) reduced fees paid to civil legal aid providers by 10% between October 2011 and February 2012, while the Legal Aid, Sentencing and Punishment of Offenders Act 2012 reduced the range of issues for which civil legal aid was available and changed financial eligibility criteria for receiving assistance.
The NAO said that while the department was on track to significantly slash spending on civil legal aid in a short period of time, it had failed to think through the impact the changes would have on the wider system.
Margaret Hodge MP, chair of the Committee of Public Accounts, said: "It is all well and good that the Ministry of Justice is meeting its objective of cutting spending on civil legal aid, but it is doing this without knowing what the knock-on effects might be for other organisations and people needing advice.
"The Ministry is out of touch with reality and has shown no understanding of the wider cost of its reforms."
She added: "It is concerning that there were 8,110 more cases involving children in which neither parent had legal representation last year, an increase of 89% from 2012/13."
The NAO also estimated the the increased number of people representing themselves in family courts could cost the public purse a further £3.4 million a year.
This is because cases involving litigants in person take 50% longer.
The spending watchdog has recommend that the MoJ develops measures to evaluate the impact of the reforms , including estimating any wider costs to the courts system.
Malcolm Richardson, deputy chairman of the Magistrates' Association and an experienced family court magistrate, said: "People representing themselves is on the rise in family courts and 97% of our members tell us that it is having a negative impact on their work.
"We are concerned that there is little confidence in the targeting of funding to those in need, as this will only add to the disadvantages of people going through the family courts without legal representation."
The NAO said it expects £300 million to be saved as a result of the legal aid reforms.
The spending watchdog also found that fewer individuals are using mediation for family law proceedings as an alternative to the courts, with a decrease in 17,246 - 56% - in family mediation assessments in the year after the reforms.
An MoJ spokesman said: "At the time our reforms began we had one of the most expensive legal aid systems in the world at around £2 billion per year. Given the financial crisis inherited by this Government, there was no choice but to find significant savings. This report confirms we are doing just that.
"This was never going to be an easy process, but we have made the necessary reductions whilst ensuring legal aid remains available where people most need legal help. These changes were debated extensively and approved by Parliament during the passage of the Act."
Shadow justice secretary Sadiq Khan said: " This damning report by the National Audit Office completely exposes David Cameron's reckless assault on access to justice for what it really is: bad value for money and leaving hundreds of thousands without proper legal advice.
"Labour warned that denying people legal aid in this rushed way would merely see costs rise in other areas but sadly the Government failed to listen.
"They claimed they would instead divert people into mediation but these figures reveal there have been 17,246 fewer mediation assessments in the last period. On every measure, David Cameron's Government have completely failed on legal aid."