The new Alien and Thor movies will be filmed in Australia with the Turnbull government offering Hollywood studios $47 million in grants to lure the blockbusters, which are expected to create about 3000 local jobs.
Announcing the projects, Foreign Affairs Minister Julie Bishop and Communications Minister Mitch Fifield said the films would generate $300 million in investment in Australia.
Sir Ridley Scott's latest Alien film, which is yet to be given a title, will be the sixth instalment in the series after 2012's Prometheus, which was a prequel to his 1979 original. It is being made by 20th Century Fox studios. 
Thor: Ragnarok, based on the Marvel Comics superhero, will star Australian actor Chris Hemsworth and will be the third in the series. It is being made by Walt Disney studios.
Production for both films will start next year, though locations are yet to be announced.
Sir Ridley's project will be a second Prometheus film. The veteran British director was recently quoted as saying that he may make up to four Prometheus films, at the end of which the saga will link up with the beginning of the original Alien movie.
The first Prometheus told the story of a humanoid alien race that created life on Earth but then, disgusted with its creation, made an early version of the eponymous alien creatures from the 1979 original with the intention of sending them to Earth to destroy humanity.
Complicating matters, a new Alien movie, set after the existing series, is set to be filmed by District 9 director Neill Blomkamp.
The Thor series, based on Marvel Comics' twist on Norse mythology, chronicles the story of the crown prince of the fictional world of Asgard. It began with exile from his home world to Earth.
Hemsworth and Sir Ridley each did a video presentation as part of the government's announcement.
Hemsworth said he was "incredibly excited to be coming back home to work".
Sir Ridley said he looked forward to working with "your talented camera crews and designers".
Ms Bishop indicated the Gold Coast was likely to play a role after Disney filmed the most recent Pirates of the Caribbean sequel there, though that project led to the awkward public fight between star Johnny Depp and Agriculture Minister Barnaby Joyce over the actor's pet dogs, which had not gone through quarantine.
Senator Fifield said Prime Minister Malcolm Turnbull had taken a "minute by minute interest" in the projects.
He said the films would generate more than $300 million in investment in Australia.
"What it means is 3000 direct jobs for Australians ??? It also presents the opportunity to showcase Australia, to let people know that this is a terrific place not only to do work but also for tourism."
Every job created in film and television supported 3.75 jobs in other industries and every dollar of turnover created turnover of $3.52 in related industries, he said.
Ms Bishop said she had spoken to a range of powerful Hollywood figures on a recent visit to the US and detected enthusiasm for Australia-based projects.
"All expressed a very keen interest to invest in significant new film production projects right here in Australia. They specifically spoke about the value in Australia as a filming destination, the quality and variety of our locations, but more importantly our highly qualified and talented workforce, our embrace of innovative technology, our stable economy, our dollar. All this makes Australia an attractive destination."
Sir Ridley has previously said that Canada was being considered for the Prometheus sequel.
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