The default position
In New South Wales there is no general legal obligation on a tree owner to stop their tree growing over the boundary. The common law instead gives the affected neighbour a right of abatement: you may cut back branches and roots that encroach onto your property.
That right comes with real limits, and they are where most disputes start.
You cut to the boundary line, not beyond it. Anything past the boundary is damage to somebody else's tree.
You may not enter their land. No standing on their side of the fence, no ladder over the boundary, no reaching across with a pole saw from their driveway. Doing so without permission is trespass.
You pay. The cost of the cutting is yours, because you are exercising your right, not enforcing their duty.
The cuttings remain their property. Which is the subject of its own guide and is less obvious than it sounds.
Council controls still apply. Abatement is not a permit. If the tree is protected, the approval process applies to you too.
Get the Act right
The relevant legislation here is the Trees (Disputes Between Neighbours) Act 2006 (NSW). It is worth naming, because a great deal of what circulates online about Australian tree disputes quotes the Neighbourhood Disputes (Dividing Fences and Trees) Act 2011, which is Queensland law. The two regimes are not the same — Queensland has a formal notice-to-remove process that New South Wales does not.
Under the NSW Act, an owner or occupier of land can apply to the Land and Environment Court for orders about a tree on adjoining land where the tree has caused, is causing, or is likely in the near future to cause damage to property, or is likely to cause injury to any person. Part 2A deals separately with hedges obstructing sunlight or views.
What the Court can do
If an application succeeds, the Court can order a wide range of things: that the tree be pruned or removed, that it be maintained in a particular way, that works be carried out on either property, that compensation be paid for damage already done, and who pays for what.
Crucially, the Court will not entertain an application from somebody who has not first made a genuine effort to sort it out with the neighbour. Notice has to be given, and the file will show whether you tried.
What to do before it gets legal
Talk to them, in person, once, before anything else. A substantial proportion of these disputes come down to the tree owner not having noticed. Follow it up in writing so there is a record, and keep it factual rather than aggrieved.
Photograph everything, dated: the overhang, any damage, the gutters, the fence. If there is a real safety issue, get an arborist's written opinion. A professional assessment saying a limb is structurally compromised changes the conversation entirely, and it is what the Court would want to see anyway.
Offer a practical way forward. Splitting the cost of a crown reduction is cheaper for both of you than either of you litigating, and it usually keeps the tree, which is often what the owner actually cares about.
The practical guides
For the physical side of the job — where the boundary actually runs and how to cut without hurting the tree — see cutting overhanging trees from neighbours. For the step-by-step of resolving a dispute, see neighbours' trees overhanging my property. If the tree belongs to the council rather than a neighbour, that is a different process again.
None of this is legal advice about your situation. For a quote on pruning work either side of a boundary, ring (02) 4210 5885.
Frequently asked questions
Does my neighbour have to cut branches that hang over my fence?
Generally no. There is no automatic duty on a tree owner in New South Wales to keep their tree inside their boundary. What you have instead is a right to cut back what overhangs, at your own cost, to the boundary line. If the tree is actually causing damage or a risk of injury, that is a different matter and the Land and Environment Court can order the owner to act.
Which law applies in New South Wales?
The Trees (Disputes Between Neighbours) Act 2006 (NSW), alongside the common law. A great deal of material online quotes the Neighbourhood Disputes (Dividing Fences and Trees) Act 2011, which is Queensland legislation and does not apply here. If something you are reading cites the 2011 Act for a NSW dispute, it is the wrong jurisdiction.
Do I need council approval to cut an overhanging branch?
Possibly. The right of abatement does not override council tree preservation controls. If the tree is protected under your council's controls, substantial pruning needs approval whether the branch is over your land or not. For a small branch it is rarely an issue; for a significant limb off a mature tree it very much is.