F1 testing 2017: Top three teams tipped to be more than 1s clear

Although there remains a great deal of uncertainty about which team holds the edge as pre-season testing enters its final day, Steiner is convinced the big three hold a significant advantage, which is primarily down to the resources they have to work on aerodynamics.

"Between the top three and the other ones it is between one second and 1.5 seconds I think," he said.

"It is aero, and we need to work on it. It won't be for Australia.

"The big teams will always have more resources to do it, and this is to be expected.

"There is no surprise that Mercedes and Ferrari and Red Bull came out better than everybody else.

"They have more resources to do more testing and that is what it is."

When asked if there was a danger that 1.5 seconds could grow as the development race takes hold, Steiner said: "It will not get smaller in my opinion.

"But maybe the gains further up you get the smaller they get, so the smaller teams can make bigger gains because they are further behind."

The midfield pack appears to be very close, with Steiner unsure of where his team stacks up.

However, he believes Williams could emerge as the best of the rest.

"I think the Williams is a little bit better than the big group, but we need a few more days to be sure, and in Australia we will find out," he said.

Williams performance chief Rob Smedley was more cautious about where his team would end up.

"What we can take from this week's running so far, and that is why we are trying to notch up more than 160 laps a day, is that there doesn't appear to any fundamental problem with the car," he explained.

"We are happy with that. Where we will fall out we will get a reasonable idea in Australia.

"But you will not get a really good idea until you have done four races.

"It is not really important where you are now, because recovery will be so quick for yourself or your competitors if you are having issues.

"So the main thing is to get development on the car as quickly as possible."