The courts service could be ordered to pay for lawyers and experts in family cases 'as a last resort' where the Legal Aid Agency has refused to do so, following a ruling by Sir James Munby.
The head of the Family Division was giving judgment in three unrelated cases concerning private law matters in which a father was seeking to 'play a role' in the life of a child living with the mother.
In each case problems arose because the mother had public funding for representation and the father did not.
The cases, Munby said, are 'typical' of their kind and 'representative of many others'.
Munby highlighted the impact the Legal Aid, Sentencing and Punishment of Offenders (LASPO) Act 2012 has had on courts, citing a 'drastic reduction' in the number of represented litigants in private law cases and increased demand for pro bono assistance.
The problems, he said, have been 'very considerably exacerbated' by LASPO, although he accepted that they pre-date the act.
The effect of LASPO is that public funding is no longer available for most private law children cases, unless they can meet the test for exceptional funding, which the High Court recently ruled was too high (Gudanaviciene and Others v director of legal aid casework and another  EWHC 1840 (Admin)).
Munby cited statistics from the Ministry of Justice showing that eight applications for exceptional funding in family cases were made between April and December 2013.
He expressed no opinion on whether the scheme is working properly, but observed: 'If the scheme is indeed working effectively, then it might be thought that the scheme is inadequate, for the proper demand is surely at a level very significantly greater than eight or nine cases a year.'
The cases involved are referred to only as Q v Q, Re B (A Child), and Re C (A child).
Q concerns a father who does not speak English with a conviction for sexual offences against children, who was unable to challenge an expert report after public funding was withdrawn. The other two cases involve allegations of rape made by mother against father, which are denied.
Munby said: 'The absence of public funding for those too impoverished to pay for their own representation potentially creates at least three major problems: first, the denial of legal advice and of assistance in drafting documents; second, and most obvious, the denial of professional advocacy in the courtroom; third, the denial of the ability to bring to court a professional witness whose fees for attending are beyond the ability of the litigant to pay.'
He said: 'I have concluded that there may be circumstances in which the court can properly direct that the cost of certain activities should be borne by HMCTS.
'I emphasise that (the provision of interpreters and translators apart) this is an order of last resort. No order of this sort should be made except by or having first consulted a High Court judge or a designated family judge.'
He added: 'The MoJ, the LAA and HMCTS may wish to consider the implications. That is a matter for them.'
A spokesman for the MoJ said the ministry is 'considering the judgment'.
The Law Society's head of family and social justice Mark Poulson said: 'The judgment's significance is as a signal to policymakers. It says that in private law Children Act proceedings where exceptional funding is not granted, and interpreters or experts deemed necessary to resolve proceedings justly are put out of the court's reach; or Article 6 and 8 rights are put at risk because legal representation is not funded by the LAA - for example, where an alleged perpetrator is set to cross-examine an alleged victim - then the court will consider ordering costs against HMCTS, on the basis that some part of the public purse has to meet the state's obligations.'
Paulson added: 'This is really an exhortation to the MoJ and LAA to sort things out before matters reach that stage.'
Read the full judgment.