2016 Mercedes-Benz C-Class Cabriolet revealed

The cost of top-down motoring in a Mercedes-Benz is about to get $20,000 cheaper.

The new C-Class Cabriolet unveiled at Geneva, is expected to start from $70,000, making it the most affordable drop-top Mercedes to date in Australia.

It will not even attract Luxury Car Tax. Sipping less than 7.0L/100km, it is deemed a "fuel-efficient" car and so the LCT doesn't take effect until the price goes beyond $75,375 — rather than the nominal $63,184 threshold that gets certain thirsty variants of family cars such as the Toyota Kluger, Ford Everest and Nissan Patrol slugged with LCT.

The first ever C-Class Cabriolet is due in Australia in December, just in time for summer, alongside the coupe.

It replaces the E-Class Cabriolet, starting from $89,900.

As with the C-Class sedan, engine options run from a 2.0-litre turbo petrol to a 3.0-litre V6 twin-turbo.

The price of the C-Class Cabriolet is not much dearer than the smaller Audi A3 and BMW 2 Series

Eventually, the booming 4.0-litre V8 twin-turbo from the AMG performance division will be added to the open top tourer to create the C63 AMG cabriolet.

Mercedes-Benz is bracing itself for a surge in sales with the new convertible. The average transaction price for the predecessor was in excess of $100,000 by the time on-road costs and options were added.

"It was just that little bit out of reach for a lot of potential customers," says a Mercedes-Benz Australia spokesman.

"But with the new model, we've realigned the price and we think this will open the car up to a lot more customers."

The price of the C-Class Cabriolet, a full-size four-seat convertible, is not much dearer than the smaller Audi A3 and BMW 2 Series drop-tops.

It also undercuts its direct rivals, the Audi A5 convertible and BMW 4 Series cabrio, by between $10,000 and $20,000.

Last year, the Mercedes E-Class coupe and convertible were outsold by the BMW 4 Series coupe and convertible by two-to-one (957 versus 1921), according to figures from the Federal Chamber of Automotive Industries.

With the aggressive new price, Mercedes-Benz hopes to reverse that sales ratio.

Will the C-Class Cabriolet's new price tag tempt you over an A5 or 4 Series? Let us know in the comments below.