Formula 1 tests prove field has closed up even more in 2013 - Lotus

After a 2012 campaign that produced seven different winners from the first seven races - and a title fight that went all the way to the final round in Brazil - Allison says early indications from testing point to things being tighter still this season.

AUTOSPORT analysis: What we learned from test two

"What is absolutely clear from the first couple of tests is that it is close at the front," said Allison at a FOTA Fans Forum event in Barcelona on Wednesday.

"Of course things can change, and we are not wearing the Melbourne clothes on the car yet.

"It was close last year but the indications are that it is closer still this year. It would be a bold person who could make a prediction on who will win this year. It could be any one from four teams."

F1's final pre-season test commences at Barcelona on Thursday. All teams are set to introduce their final updates at the test ready for next month's Australian Grand Prix.

And although the four days of running look set to be hit by poor weather, the update situation should provide a better indication of the frontrunning pecking order for Melbourne.

Passive DRS set to add new factor

F1's competitive balance could be further shaken up later in the campaign too, with Allison revealing that Lotus will only bring its passive DRS into play once the season is under way.

"We tried to make it work last year, and it is fiercely complicated to make it work," he said. "There is a tantalising gain to be had from it if you can make it work, a gain you would rather have than not have, but it remains a difficult thing.

"We have done a little bit of intermediate work at the last test on getting ready for it, and will do some more on it here. But I don't think at the end of this test we will be ready to go with it 100 per cent.

"But we will be closer to it, and I am hopeful that at some point this year we will be ready to make it work and make it pay."