PARIS - U.S. planemaker Boeing will launch a larger version of its lightweight 787 Dreamliner this week with up to 100 orders worth just under $30 billion (19 billion pounds), industry sources said on Sunday.

The latest addition to Boeing's fleet, the 323-seat 787-10, is partly designed to serve fast-growing routes within Asia and sharpens a fight with Europe's Airbus for sales of the latest generation of efficient, carbon-composite jets.

The decision to go ahead and build a new version, backed by up to 100 orders spread between five or six launch customers, is expected to be announced on Tuesday at the Paris Airshow. Some orders may be converted from existing demand for smaller jets.

Boeing declined comment.

"We have no comment but we are having discussions with our customers about the potential for the 787-10X," a Boeing spokesman said, referring to the working name given to the project while Boeing targeted potential customers.

The 787-10 Dreamliner -- a "stretched" version of an existing model -- would compete in part with Airbus's next-generation A350, which carried out its maiden flight on Friday.

Boasting fuel savings because of a lightweight structure, it is also expected to challenge a revival in sales of the traditional metallic Airbus A330, which has been snapped up by many airlines during three years of 787 delivery delays.

But the European company insists the reliability and availability of its most popular long-haul jet will remain a selling point for years, as well as its cheaper price.

The 787-10 is expected to have an official price tag of around $280-290 million per plane, $40 million or so more than other 787s, and is due to enter service in 2018-19. In practice, aircraft are usually sold at steep discounts.

Singapore Airlines has already agreed to buy 30 jets if the 787-10 is launched. Others widely linked to the project include United Airlines, British Airways and leasing company, Air Lease Corp.

After a bitter market share battle for smaller planes, rivalries over high-margin big jets look set to dominate the June 17-23 air show where demand from emerging-market airlines and leasing companies is expected to fuel hundreds of orders.