Slack attitude will get us beaten - Mercedes F1 boss Toto Wolff

At the halfway point of the 2016 F1 season, Mercedes is 154 points clear of nearest rival Ferrari while Lewis Hamilton and Nico Rosberg have the drivers' championship battle to themselves.

With major regulation changes looming for 2017, some teams have completely halted '16 development efforts already.

But Wolff insists Mercedes cannot take that strategy as it should not consider itself unbeatable this year.

"If you have that attitude you will be beaten," he said.

"You need to see the threat, and you need to be conscious that at any track somebody could do a better job.

"You must keep in mind that next season is important, and the change of regulations is important, so you're trying to stay pretty unemotional about the situation.

"Just deploy the best possible engineering, the way we prepare for the race, the way we execute the race and the trackside engineering.

"Equally the team in the UK needs to work as hard as possible for next year and not get drawn into 2016. That is a constant balance."

One thorny issue for Mercedes is how to handle the engine penalty Hamilton has already suggested will be "inevitable".

The champion is already on the last of his allocated turbochargers and MGU-H units, and if another is required he will be forced to take a grid drop that could hinder his championship chances.

Although Hamilton is now leading the title race for the first time this season, Wolff added: "First of all the lead in the championship mid-season is not important.

"You just need to do every weekend as good as possible and score the maximum points. At the end you can start counting.

"In terms of the engine penalty, we want to wait as long as possible, to the moment we can judge how many engine components we need to go to the end.

"We then choose a track where the penalty maybe isn't as hard for him in some ways, but that decision we haven't made.

"We need to wait until after Hockenheim [this weekend's German Grand Prix] and then it will be reassessed."