"They were not the conditions we wanted; it rained for two of the three days," the McLaren reserve driver, who was released for one final test with F1's new tyre supplier, is quoted by EFE news agency.
"It was important to try the tyres on turn eight, a corner more demanding than any other in the championship," he added.
De la Rosa, 40, travelled from Istanbul to Kuala Lumpur, where this weekend most insiders are expecting Red Bull to pull out an even greater advantage.
They were not the conditions we wanted; it rained for two of the three days
"The cars that were good in the few fast corners in Australia will be even better in Malaysia," he acknowledged. "But who knows. My team (McLaren) has done a spectacular job in the past weeks."
Meanwhile, Fernando Alonso spent his time between Melbourne and Malaysia on beautiful Hamilton Island, at a luxury $2,300 per night resort.