BMW's Rolls-Royce will debut a two-door coup version of its Ghost model, known as the Wraith, which the company says will be its most powerful vehicle yet.
Meanwhile Bentley, part of the Volkswagen empire, will unveil its updated Flying Spur, its speediest ever four-door model.
The two German-owned brands hope the new launches will extend an upturn in their markets, which has been boosted by recovering demand in the United States and strong growth in Asia, where customers are increasingly attracted by the history and status of brands such as Rolls-Royce and Bentley.
The United States and China have traded positions as Rolls and Bentley's largest markets in recent quarters.
"The Wraith, along with the Ghost, is there to compete with Bentley's Continental GT, which at a slightly lower price has been a huge success," said IHS automotive analyst Christoph St rmer. "Bentley is looking for success with its Flying Spur, which is an all-new vehicle, because the predecessor didn't deliver the sales they were looking for."
"Rolls and Bentley are direct competitors and are like the last men standing in the ultra-luxury, high-end segment so the fight for attention of the super-rich in Geneva will be fierce," he added.
Company insiders say the Wraith, a name first used by Rolls in 1938, will produce as much as 600 horse power from a twin-turbo 6.6-litre V12 engine.
So far only two "teaser" images of the Wraith have been released, showing a shallow-sloping "fastback" design similar to that seen on smaller sports cars, while the rear appears similar to the Ghost, with the addition of large exhaust tailpipes at either side of the vehicle.
Torsten M ller- tv s, chief executive of south east England-based Rolls, is confident the new model will "draw superlatives" when it is unveiled in Geneva.
Bentley claims its redesigned Flying Spur, which has a 6-litre, 12-cylinder engine generating 616 horsepower and capable of reaching a top speed of 200 miles per hour, will set "a new luxury performance sedan benchmark".
The Spur has a lower, wider appearance than its predecessor with sharp lines and gently curvaceous surfaces, according to Crewe, north west England-based Bentley.
Bentley was owned by Rolls-Royce for some 70 years, during which time the pair offered similar models. However, since the two parted ways in 1998 they have ruled different segments of the ultra-luxury car market.
Rolls had tended to focus on making larger, more luxurious cars such as the Phantom. But with the 2009 launch of the Ghost, Rolls has looked to take a slice of the market for sportier luxury cars, which Bentley dominates with its Continental range.
Some critics say the German influence has led Rolls-Royce and Bentley cars to lose their British character.
Yet sales have flourished - Rolls sold a record 3,575 cars last year, up from 1,002 in 2009. Bentley, meanwhile, delivered 8,510 cars in 2012, 22 percent more than the year before.