Swedish manufacturer Saab is upgrading its bid for Brazil's long-delayed FX-2 jet fighter purchase plan, even as it weighs challenges from formidable rivals Boeing and France's Dassault.

Saab is one of the three leading contenders for Brazil's jet fighter replacement program, said to be worth $6 billion-8 billion but wants to make sure its jet will compete successfully for roles in both the Brazilian air force and navy.

Boeing's F/A-18 Super Hornet and Dassault's Rafale-M have already demonstrated their multirole fighter capabilities extend from air force to naval operations. Saab ran tests on a naval version of its Gripen NG with the aim to show that its jet, if successful in the FX-2 competition, will be equal to the tasks demanded of an all-rounder combat aircraft.

The three companies have invested millions in positioning themselves for a Brazilian decision on the FX-2 acquisition program, which is no nearer the crunch time than it was at when Brazilian President Dilma Rousseff put off consideration of the project last year.

Brazil's FX-2 jet fighter acquisition program coincides with a vigorous campaign by the government and local defense industry to develop indigenous aviation industry.

The long delay in the FX-2 program has fed speculation that Brazil may push off again a decision on buying new jet fighters to replace its aging MiG planes. There are also signs the government in backing Brazilian industry initiatives to develop manufacturing capability related to the jet fighter program as much as possible.

Brazil's Embraer has advanced aviation manufacturing capacity that moved over a few years from executive jet making to light attack aircraft and tactical transport and airborne jet refueling systems. But Embraer is many years from developing a jet fighter all on its own.

Saab remains serious about its "Sea Gripen NG" and has been working on the idea since their May 2011 announcement, Defense Industry Daily said on its website.

The Brazilian navy is expected to buy its own fighters to equip a new aircraft carrier and will expect its aircraft to be the same type as those to be chosen by the air force at the end of the FX-2 competition.

That prospect has pitted Saab against proven naval fighters Boeing's F/A-18 Super Hornet and Dassault's Rafale-M. The plane maker recently organized a test flight for its JAS-39D "to verify the design's basic suitability for naval conversion," Defense Industry Daily said.

Besides Brazil, Saab identified future demand for naval fighters in countries like India, Italy and the United Kingdom which, in the coming years will be commissioning new aircraft carriers in their navies, Saab's Gripen blog said.

"According to Saab, there is a real and viable market for this type of aircraft," former Brazilian naval aviator Romulo Sobral said in the blog post.

Aiming this market, the company is developing a naval version of JAS-39 Gripen, called "Sea Gripen," which aims to be a variant of its Gripen NG contender in Brazil's FX-2 program.