MugelloFormula 1 teams are gearing up for their first proper in-season test for four years, which starts at Mugello on Tuesday, with those involved in no doubt that any progress made there will help play a defining role in the outcome of the World Championship.

The first four races have proved just how competitive the field is this year, with almost nothing separating the leading contenders in the battle for victory. With further complications caused by the sensitive nature of this year's Pirelli tires, teams have been left with a huge workload to try and get through at Mugello to ensure that they can hit the ground running at the next race in Spain.

A lot of the interest in Mugello will be on Ferrari, which is set to start working on the update package that it hopes will lift it nearer the front of the grid. The team braced itself for a tough start to the campaign, with is F2012 lacking in performance, but Fernando Alonso's exceptional driving has kept him firmly in contention for the championship, as he lies just 10 points off leader Sebastian Vettel after the flyaway events.

The full package of developments for Ferrari – which are believed to include new exhaust configurations as well as sidepod and bodywork tweaks – are not expected to be ready until the Spanish GP. However, some of it is expected to be ready in time for this week's running.

Alonso himself is under no illusions about how important the next few weeks are for himself and Ferrari, if they are not to squander their efforts in the first four races.

"The team is working day and night, and Felipe and I trust the team and we trust that the next updates will come," said the Spaniard. "I think the Mugello tests and the next races are an important point for us, so hopefully we can start a different championship from that point on."

Mercedes is another team eager to make the most of its three days running, with the W03 having shown itself to be quick in the right conditions, but inconsistent in delivering that peak performance.

Although the Mugello test is the only opportunity teams will have during the season to evaluate new components and conduct work that is not normally possible on a grand prix weekend, the choice of venue has led to questions about the ultimate value of what will be learned from car updates.

Mugelllo's high-speed nature is not typical of many F1 venues, with its setup and aerodynamic demands only really relevant for tracks like Silverstone and Suzuka. In particular it lacks the slow speed turns that are so typical of forthcoming races in Monaco, Canada and Valencia. Lotus trackside operations director Alan Permane said that even with the limited value of Mugello, there were still benefits from the test.

"The track is only representative of Silverstone, maybe, so I think it will be more about trying things we cannot do on race weekends," he said.

"On race weekends we don't have tires to test things, so we can run different suspension setups in Italy for example. These are things that require complicated changes, so we can hopefully understand the fundamentals over the course of the week, rather than just aero updates that we can do on race weekends."

McLaren is the only team not using its race drivers over the course of the week, with Gary Paffett and Oliver Turvey conducting duties instead of Lewis Hamilton and Jenson Button.

HRT is the only team that has elected not to take part in the test, because it wants to focus its efforts on its new factory move.