Geotargeting rel alternate - how to launch an international site?

Question

Hoping you can help me out with some best practice here. I run an Aussie based job board called the Backpacker Job Board. The site ranks really well and has plenty of traffic.

I want to launch a New Zealand version of the site. I've got a stripped down version of the site at the following URL. It has the same categories - but different content. (currently blocked by robots.txt while I develop).

Is it possible that launching this NZ site will cause problems for the rankings of my .com.au? The site structure and code is pretty much the same.

Furthermore, noting that the job listings will be unique to each site but the categories would be the same, would it be worthwhile using the rel alternative tag on category pages? Is this more for languages rather than for geotargeting?

eg.

<link rel="alternate" hreflang="en-au" href="http://www.example.com.au/jobs/fruit-picking-jobs/" />
<link rel="alternate" hreflang="en-nz" href="http://www.example.co.nz/jobs/fruit-picking-jobs/" />

These aren't exactly translations of each page rather their own distinct category. ie. One is for fruit picking jobs in Australia and the other for Fruit picking jobs in New Zealand.

Thoughts?

Answer 1

It doesn't matter if they aren't translations, they can be used for location specific URLs too:

Use hreflang for language and regional URLs

Your content has small regional variations with similar content in a single language. For example, you might have English-language content targeted to the US, GB, and Ireland.

I would use hreflang in this situation, as well as making sure Google displays the correct site for a given search, it can also help Google understand your sites are connect, the same company but location specific sites, rather than a website copying content from another website. As mentioned in this video from Matt Cutts at Google:

How can I tell Google that multiple domains are related?