Lewis Hamilton says the forthcoming Spanish Grand Prix will provide the biggest test for Formula 1's new rules.

F1 introduced a combination of changes for 2011 in an attempt to make overtaking easier, including tyres that go off quickly and the DRS passing aid.

Hamilton said: "It will be interesting to see how the DRS affects the racing.

"Typically, it's been very tough to overtake at Barcelona because the best opportunity - into the first corner - is too fast to make a pass stick."

Hamilton, who is the only man other than Red Bull's Sebastian Vettel to win a race so this year, said the layout of Barcelona's Circuit de Catalunya was likely to make overtaking much more difficult than it has been so far this year.

"It's always been too hard to really get alongside another driver into the [first] corner," he said.

"But we benefited from two great races in China and Turkey because the DRS area led directly into a heavy braking zone, meaning it was possible to get two bites of the cherry: using the slipstream and using the braking zone.

"In Barcelona, it's likely to be less clear-cut."

The DRS, or drag-reduction system, gives drivers a straight-line speed boost by moving a part of the rear wing. This reduces the downforce the wing creates and therefore cuts drag.

Drivers can use it in a specified zone on the track if they were within a second of the car in front at a designated point before that zone. The driver defending his position cannot use his wing.

At Barcelona, the DRS zone is on the main straight.

Just as influential have been the new Pirelli tyres, which have been deliberately designed to degrade more quickly than the Bridgestones used last year.

This has created a situation where drivers whose tyres have different levels of wear have vastly differing amounts of grip.

That means the driver with older tyres finds it almost impossible to defend his position.

MARTIN BRUNDLE'S COLUMN quote TV audiences are significantly increasing, media coverage is stronger than ever, and the F1 paddock is buzzing ages after the race has finished Read more here external-link

Ferrari's Fernando Alonso, who finished third behind the Red Bulls of Vettel and Mark Webber in Turkey on Sunday, believes that the tyres were much more influential in creating passing opportunities in Istanbul than the DRS.

The Spanish double world champion said he was warming to the new rules, which have been criticised in some quarters for creating too much action and lending a sense of artificiality to F1.

Hamilton, too, has said he "enjoys" the new-look F1, saying the races are "more exciting".

The final change this season is the reintroduction of the Kers energy recovery and power-boost system, which gives drivers a boost of 80bhp for up to seven seconds a lap.

Hamilton used his Kers to pass Vettel for the lead at the Chinese Grand Prix in an unconventional spot.

But Ferrari president Luca di Montezemolo has criticised the new rules.

quote In the last race there were 80 pitstops. Come on, it's too much

"We have gone too far with artificial elements," Di Montezemolo told CNN external-link .

"It's like, if I push footballers to wear tennis shoes in the rain. To have so many pitstops - listen, I want to see competition, I want to see cars on the track. I don't want to see competition in the pits," he explained.

"In the last race there were 80 pitstops. Come on, it's too much. And the people don't understand anymore because when you come out of the pits you don't know what position you're in.

"I think we have gone too far with the machines, too many buttons. The driver is focalizing [focusing on] the buttons, when you have the authorization to overtake. We have gone too far.

"Ferrari will push a lot with the authority - with the respect that we have to the federation and the other teams - to avoid going too far with F1. Because I think it can create problems for the television people and on the racetrack."

The 2008 world champion's views on the Spanish race on 22 May being a test for the efficacy of the new rules are echoed by his team principal Martin Whitmarsh.

"I'm particularly interested to see how the 2010 rule-changes affect the grand prix," Whitmarsh said.

"We've seen how DRS and Kers hybrid have influenced the racing so far this season, so we'll see how things progress at Barcelona given that the Spanish Grand Prix has previously shown limited opportunities for overtaking."

Whitmarsh added that McLaren would try again in Spain to introduce new parts that they were unable to use in Turkey for reliability reasons.

"As we saw in Istanbul last week, there is always risk inherent in bringing any upgrade to the circuit - particularly following the absence of testing," Whitmarsh said.

"For Barcelona, we're planning to re-introduce some of the proposed upgrades initially scheduled for introduction in Istanbul.

"Once again, however, they'll only be introduced if their initial deployment on Friday proves successful."