Kovalainen is now consistently running with the 2009 rear wing in testing
McLaren chairman Ron Dennis has insisted McLaren will be title contenders in 2009, despite an apparent lack of pace in pre-season testing.
World champion Lewis Hamilton and team-mate Heikki Kovalainen lagged behind their rivals in testing ahead of the Australian Grand Prix on 29 March.
But Dennis told BBC Sport: "Whatever performance level McLaren have today we will be a competitive racing team.
"That means we will be fighting for the world championship."
While Ferrari have been consistently fast during pre-season testing, McLaren appear to be some way off the pace of their main rivals.
During this week's test in Barcelona, McLaren's Kovalainen was more than two and a half seconds down on Nick Heidfeld's fastest time for BMW Sauber on Monday.
Ferrari's Kimi Raikkonen topped Tuesday's timesheets, while another low-key showing for McLaren resulted in Kovalainen being 1.677 seconds adrift.
Over a string of consecutive laps, McLaren are also running behind Ferrari, BMW Sauber, Renault, Toyota and the new Brawn GP cars, which only made their track debut on Friday.
However, Dennis underlined the importance of not reading too much into testing times, when comparisons can often be skewed by each team's individual programmes.
"The objective is to go to Australia and be the most competitive car there, not to come out of every single test at the top of the timesheets," he said.
"Testing is about a disciplined approach to making the car go faster and you have to ignore the performance of the other teams."
The raft of rule changes for the new season means the MP4-24 is vastly different to Hamilton's 2008 title-winning car, with reduced aerodynamics and slick tyres.
McLaren have raised eyebrows by running last season's rear wing - which is much lower and wider than the 2009 version - during early testing in Portugal and Jerez.
We had a strategy for this year to leave it to the last possible moment to produce our aerodynamic package
McLaren chairman Ron Dennis
Although the McLarens are now only using this season's component in Barcelona, Dennis conceded the development of the car is a little behind schedule.
"We lost some time," stated Dennis, who stepped down as team principal at the end of February, handing over the reins to Martin Whitmarsh.
"We had a strategy for this year to leave it to the last possible moment to produce our aerodynamic package for the Australian Grand Prix.
"That in itself gave us some production challenges and we have really only started to run the car in the last day with the Australian aero package.
"We ran the 2008 rear wing because it was more relevant in its performance to the wing that we are going to have in Australia.
"It doesn't mean you are lost or that you don't know what you are doing.
"Whereas our main competitors are finishing testing in two days we still have the ability to test next week in Jerez.
"When we get to Australia that will be the first measurement of everyone's performance.
"We expect our car to go faster with every Grand Prix and we expect to maintain our pace to allow us to win the world championship."
The 2009 season begins in Melbourne with first practice at Albert Park on 27 March.