Is a licence from another state valid in New South Wales?

Not automatically. Licensing is administered state by state and there is no national register. Mutual recognition schemes exist and can let a licence holder apply to be recognised in another jurisdiction, but that is an application the tradesperson has to have made — it is not automatic, and the register for New South Wales is what settles it.

What percentage of NSW businesses publish an ABN you can check?

11.8% of the 10,493 NSW businesses in this directory, against 9.8% nationally.

Does an unlicensed tradesperson have to fix bad work?

Consumer guarantees under the Australian Consumer Law apply regardless of whether the tradesperson is licensed — an unlicensed operator cannot escape them by being unlicensed. Enforcing them is another matter, which is why the licence check is worth the minute it takes. If it has already gone wrong, see the guide on what to do when work goes wrong in New South Wales.

Check a tradie licence in NSW

Short answer

In New South Wales, licences are issued and published by NSW Fair Trading, covering builders, electricians, plumbers and specialist trades. Search the licence number the business gives you on that register before work starts — it is free and takes about a minute. There is no national licence register in Australia, so a licence from another state does not automatically apply to work done in New South Wales.

Licensing in Australia is a state matter. There is no national register, no single number to look up, and a licence issued in one state does not automatically authorise work in another. In New South Wales, the authority is NSW Fair Trading.

Which register to search in New South Wales

NSW Fair Trading covers builders, electricians, plumbers and specialist trades.

NSW Fair Trading runs a single public licence check covering builders, electricians, plumbers, air conditioning and a long list of specialist trades, so one search answers most questions. It returns the licence class as well as its status, which matters: a licence to do general building work is not a licence to do electrical work, and the class is where that distinction lives.

What to actually look at when the register returns a result

That the licence is current, not expired or suspended. An expired licence is the single most common problem a check finds.
That the name on the licence matches the name on your quote. A licence held by a related company is not a licence held by the business you are contracting with, and it is the contracting entity that owes you the work.
That the licence class covers this job. A general building licence is not an electrical licence, and a plumbing licence does not automatically include gas fitting.
Any conditions on the licence. Conditions exist for a reason and are published where the register shows them.

What 10,493 NSW businesses publish about themselves

A licence is not the only thing you can check from outside a business, and the rest is not encouraging. Across every NSW business in this directory:

What we checked	NSW	Australia
Publish an ABN we could confirm	11.8%	9.8%
Listed phone matches their own website	39.6%	39.2%
Listed phone contradicts their own website	4%	4.8%
Website responded when we checked	64.2%	64.7%
Median Google reviews	28	29

9,255 NSW businesses — 88.2% of them — publish no ABN anywhere a customer can find it. An ABN is free to obtain and free to publish, so this is not evidence of anything improper. It does mean the cheapest identity check available to you is unavailable for most of the market, and that asking is reasonable.

What a licence check does not tell you

Whether the work will be any good. A licence is a floor, not a rating.
Whether they carry insurance. That is a separate question with a separate answer, and you should ask it.
Whether the licensed person will be the one on site. Ask who is actually doing the work and whether they are supervised.
Whether they are solvent. A licence stays current right up until a business stops trading.

Common questions

Who licenses tradespeople in New South Wales?: NSW Fair Trading, covering builders, electricians, plumbers and specialist trades. NSW Fair Trading runs a single public licence check covering builders, electricians, plumbers, air conditioning and a long list of specialist trades, so one search answers most questions. It returns the licence class as well as its status, which matters: a licence to do general building work is not a licence to do electrical work, and the class is where that distinction lives.
Is a licence from another state valid in New South Wales?: Not automatically. Licensing is administered state by state and there is no national register. Mutual recognition schemes exist and can let a licence holder apply to be recognised in another jurisdiction, but that is an application the tradesperson has to have made — it is not automatic, and the register for New South Wales is what settles it.
What percentage of NSW businesses publish an ABN you can check?: 11.8% of the 10,493 NSW businesses in this directory, against 9.8% nationally.
Does an unlicensed tradesperson have to fix bad work?: Consumer guarantees under the Australian Consumer Law apply regardless of whether the tradesperson is licensed — an unlicensed operator cannot escape them by being unlicensed. Enforcing them is another matter, which is why the licence check is worth the minute it takes. If it has already gone wrong, see the guide on what to do when work goes wrong in New South Wales.

How to check a tradesperson's licence in New South Wales