Perez's team-mate Jenson Button said at Barcelona last week that he was finding the MP4-28 hard to understand, with his performances ranging from very competitive to off the pace.
Asked by AUTOSPORT if he was in the same position, Perez said unlocking the car's set-up secrets was proving tough. But he does not think McLaren is in a worse position than its rivals.
Webber tops first day of final F1 test
"I think there is a lot of work to be done in the next couple of days for us and they're very important days for the start of the season," said Perez.
"I think we would definitely like to go into Melbourne with much more information than we have at the moment. We had a couple of difficult days with problems with getting the information from the car.
"It's important that we maximise our chances. I'm sure everybody around the paddock has problems. Everybody would like to arrive in Melbourne a bit better prepared."
Perez has just one more day of testing scheduled before his race debut with McLaren in Australia.
He said it was vital that he got a better understanding of the car as the Barcelona test concludes this weekend.
"On my last day I would really like to learn about the updates we have on the car and about the set-up, and to get comfortable with the set-up," Perez said.
"The last day I was here, I was not comfortable with the set-up. We have some changes and obviously I would like to try them before Melbourne.
"But if I don't get the opportunity to try them then we have to look forward to Melbourne and there's nothing we can do."
All the photos from the Barcelona test