Trainer Archie Alexander is unsure what imported galloper Southern Rock will produce in his Australian debut at Caulfield.

Southern Rock is set to join stablemate Kiwia in a handicap over 1600m on Saturday, a race that will give Alexander a better insight into the Irish-bred four-year-old's capabilities.

Southern Rock has won four of his eight starts and started his career with Andre Fabre in France before joining Dave O'Meara's stable in England.

"He's a bit of weird horse to get a guide on so it will be interesting to see him kick off, but he has got a lot of ability" Alexander said.

"We've got no idea where this horse will get to, whether he's a benchmark horse or whether he might be a Group horse.

"And I've got no idea if he's a miler, 2000 or a 2400-metre horse.

"He's run in Listed races in England but we'll start him off quietly and see where he gets to."

Since Southern Rock arrived in Australia last year Alexander has worked on getting him to put on weight and strengthening him for the preparation ahead.

Just how far Southern Rock progresses this campaign will be revised after his first couple of races.

"This prep is a learning process with him," Alexander said.

"I've said to the owners he never wins a gallop by much, he doesn't finish far behind them by much, and only does enough.

"He doesn't pull in his gallops but at the end he doesn't want to stop, so he is an interesting one."

Alexander said Kiwia would have a brief campaign then a break ahead of a spring campaign.

Kiwia has not raced since winning the Ballarat Cup last November and Alexander said that race was likely to be a target again.

"We've on purpose brought him along slowly but he's ready for a nice first run back over a mile," Alexander said.

"He's going to have a bit of a Lloyd Williams style preparation, a couple of runs in the autumn and then put away for a break and get him up for the spring.

"The Ballarat Cup will be his spring aim, but if he happened to put his hand up for something else, I'd be happy."

Alexander is also planning to run Mirette in a benchmark 84 race over 1800m along with Buena Veloz and Write Your Name in the benchmark 78 race over 1400m.