Anyone Know This Cactus?

This cactus was photographed in a garden in Christchurch, New Zealand. It had formed a large clump on a sandy bank near the coast. The short flowers and segmented pattern on the stems looks distinctive but I could recognize it. Any ideas?

 

I now think it's most likely Austrocylindropuntia cylindrica.

 

Seems like a good guess.

 

I'm interested to see the name. I thought it looked like Opuntia, but i know so little about cacti and didn't know there really were cylindrical ones.