Alex Lowes says 'the biggest improvement' is still to come from himself despite topping both days of official testing ahead of the 2015 World Superbike Championship opener at Phillip Island.

The Voltcom Crescent Suzuki rider improved on his benchmark during the second day around the Australian circuit, stopping the clock at a 1min 30.859secs to just edge out Kawasaki's Jonathan Rea.

An intense couple of days for the rider and the team, Lowes is happy with the performance of his GSX-R1000 but insists there are improvements still to come, albeit mostly from himself.

"We've had a good day and got through a detailed test programme, there's not too much that we wanted to try that we haven't really, so it's been a difficult two days for the mechanics working really hard!

"The GSX-R is pretty good now, we'll make a few changes over the weekend depending on the temperature and some minor things to try with electronics and the chassis but the biggest improvement still to come is from me and I know a few areas I can ride differently.

"I enjoyed it a lot today, did a race-run, put a lot of effort in and tried to keep within the limits. Thanks to the lads for all the hard work, hopefully we'll keep progressing over the race weekend."