Kimi Raikkonen says Alfa Romeo's standing in the Formula 1 pecking order remains a "big mystery" heading to the opening race of the 2019 season in Australia next weekend.

Raikkonen enjoyed four solid days of running in Barcelona through pre-season testing for Alfa Romeo as the team completed the third-highest number of laps, giving it a solid footing heading into the new campaign.

The former Ferrari driver said he was impressed by the work Alfa Romeo had completed since joining during the winter, but remained uncertain how exactly it would fare compared to its rivals.

"I think they’ve been doing a good job the last year already, just growing up, but nothing is guaranteed. If we are fifth or 10th, who knows," Raikkonen said.

"I think it’s going to be quite close between the mid-pack and do your job well you’ll be higher up than on off-days when you don’t do it well.

"So we’ll just do the best job we can and go for the first race."

Asked if had any specific targets for the opening race in Australia, Raikkonen said: "It’s a big mystery, and like I said we’ll give our best and see what we get in our first race and work from there.

"We’re not 100 percent where we want to be, but I think if you ask anybody, they’re going to say the same."