The law firm behind a push to overturn a 50-year-old precedent that stops families claiming a tax deduction on childcare is entering talks with the Tax Office as it inches the case along a winding path to the High Court.

Arnold Bloch Leibler’s lead tax partner, Paul Sokolowski, told The Australian Financial Review the firm was approaching the ATO seeking its agreement to provide litigation funding under its test case funding program. At a minimum, the firm hopes the ATO will agree not to seek costs during the litigation process.