Kiwi English

I'm trying to watch some of the Spartacus TV series, which is filmed in New Zealand and stars a whole buttload of Kiwi actors, and I'm totally befuddled by the dialogue. No matter how much I strain, I'm only understanding like one word out of every five. I don't understand why I don't understand Kiwi accents. I know they're speaking English, but it's like the unfamiliar vowels and rhythm throw my brain into a tizzy. Does anyone else have problems like this?