Can I do this?

I plan on creating a garden bed along a fence that seperates the neighbours on one side of a house. (just a regular, run of the mill fence that seperates one yard from another)

The fence is chain mesh and I am putting some decorative roll out type of privacy screen on the fence. (cant remember what its called)

Now, The garden bed will be treated pine, and 60cm high.

I want to build the back of this garden bed with the same pine all the way up to the fence level to block out sound from the neighbours.

I gather this is o.k, but is it 'legal'?
Do I need permission?

Thank you.
So long as it is entirely on your property there is no problem. Keep it a few inches away from the fence to be safe. Just comply with height restrictions.
Thanks Marg. Also, do you mean 'height restrictions' of the current fence?

Thats very nice to know, I would have felt a little guilty just building it without knowing!

My only worry are the neighbours who are quite close to my property and I can hear every word they say..

They tell me that the previous neighbours were really rowdy and theyre glad theyre gone, but my guess is they were just normal and were so close together that I can hear every word they say when out on the patio.

Si all in all I gues they'll be glad I'm building this wall in discuise ;)
By height restrictions I simply mean not to go too tall too close to the fence line. Just because it is inside your yard does not mean you can go 10 ft tall right beside the fence.

Stick with normal fencing height (around 6 ft?) and you will be fine.