Mercedes is on course to launch its title-defending car on the eve of the first winter test, team boss Toto Wolff has revealed.

"We are on schedule and have a clear idea of where we are in terms of chassis and engine," he told Italy's La Gazzetta dello Sport whilst holidaying in the Austrian ski town Kitzbuhel.

Brackley based Mercedes utterly dominated the 2014 season, but Wolff says he doesn't mind "at all" that champion Lewis Hamilton has elected to keep his personal number 44 this year rather than carry the coveted number 1.

Instead, Wolff's mind is on ensuring Mercedes stays at the top of F1.

"The first goal is to assemble the car in time for mid January," he said, "when we plan a test at Silverstone.

"But only at Jerez will we have a picture of the balance of power with the opposition."

When asked if he knows when the W06 will be officially launched, Wolff answered: "No, but I do not exclude that it will happen right before the first test in Spain."

He said there is no chance Mercedes will be entering the season more relaxed, given the team's level of dominance last year.

"When you begin to relax, you begin to lose," said Wolff.

"Compared to last year, when the new formula came in, margins for improvement are smaller now and our opponents know our strengths and what they need to focus on to beat us."

Mercedes' rivals appear to have at least won an off-track battle, as the use of the 32 engine 'freeze' development tokens can now be deployed throughout 2015.

"Everything depends on the interpretation of the rules," Wolff confirmed, "the FIA offered its version and I do not see any problems.

"Certainly the freezing of engines in February is best for those who are at the front," he admitted, "but we are able to develop too."