Recent Developments in Estoppel: What Lawyers Need to Know
Recent Developments in Estoppel: What Lawyers Need to Know
Presented by Nick Kabilafkas | 29 April 2026
Estoppel law in Australia has shifted significantly in the past two years. This presentation by Nick Kabilafkas cuts through the complexity and brings you up to date with the cases that matter.
Drawing on decisions from the High Court, the NSW Court of Appeal, and recent Supreme Court judgments — including several handed down in 2025 and 2026 — Nick covers:
- Conventional estoppel — the five elements, and two critical differences from equitable estoppel confirmed in Les & Zelda Investments v Whitehaven Coal [2026] NSWSC 107
- Estoppel by encouragement and acquiescence — the refined elements following Kramer v Stone (2024) 281 CLR 484 and how Pirrottina v Pirrottina [2025] NSWCA 55 applied them
- The "clear and unequivocal" debate — the tension between Kramer v Stone and earlier authority on proprietary estoppel, and what Kronenberg v Macaulay [2025] NSWCA 195 and Penya v Penya [2026] NSWCA 73 (handed down the day of this presentation) mean for your cases
- Promissory vs proprietary estoppel — whether promissory estoppel can be used as a sword, and why the NSW Supreme Court remains bound by Saleh v Romanous despite ongoing appellate tension
- Representation, reliance, detriment and relief — practical guidance on each element, including testamentary promises, counterfactual reliance, countervailing benefits, and how courts mould relief from compensation through to conveyance
This is a technical, case-rich presentation aimed at practitioners who need to understand how these doctrines operate — and where the law is still unsettled.
Who should watch: Litigation and equity lawyers, estate and property practitioners, and anyone advising on or running estoppel claims in NSW.