McLaren has rejected any claims it has fallen behind in the development of its 2011 car.
It had emerged that that the Mercedes powered MP4-26 would not get its maiden run until after an interim 2010 car contests the opening group test at Valencia.
But Paddy Lowe, the British team's engineering director, said that McLaren sees its plans as "optimal".
"It's always been in our plans to launch it after the first test," he said.
"One of the reasons was we wanted to make use of the first test to work with the car as a stable and known platform while we understood the new (Pirelli) tyres," Lowe added.
"It also gave us a bit more time in the programme for the new car."
One theory about McLaren's approach is that the 2011 car features some key innovations that the team either wants to spend more time perfecting or shield from its rivals for as long as possible.
McLaren pioneered the so-called F-duct last year that was ultimately copied by almost every team.
"Yes, there will be some new elements," team boss Martin Whitmarsh admitted to F1's official website, "but as you can imagine I'm not prepared to add more detail at the moment."
Engineers To Ensure F1 Sounds 'Sexy' In 2013
F1 engineers will work with the sport's new engine formula for 2013 to create a "sexy" sound.
That is the claim of Fernando Alonso, amid fears F1's formidable engine note is not reduced to a feeble buzz after the normally-aspirated V8s roar for the last time next year.
Asked about the likely sound of the four-cylinder turbo engines in 2013, Ferrari driver Alonso said on Thursday: "For the driver, the change will not be a big one.
"From the cockpit, we hear only five or 10 percent of the ambient noise anyway," the Spaniard said at Ferrari's media event in the Italian Dolomites.
"For the fans, of course, it is important, but I am sure the engineers will work for example with the exhaust to ensure that the sound is sexy enough," added Alonso.