The Houston Astros have fired general manager Jeff Luhnow and manager A.J. Hinch after the duo were suspended following an MLB investigation into allegations of sign stealing.

Luhnow and Hinch were given year-long bans by MLB while Houston were fined $5million and have been forced to forfeit their first and second-round picks in the 2020 and 2021 drafts.

In a statement, MLB commissioner Rob Manfred said the Astros were warned about the league's policies on sign stealing in September 2017 and "took no action" to comply with these during their run to a maiden World Series title later that season.

"While it is impossible to determine whether the conduct actually impacted the results on the field, the perception of some that it did causes significant harm to the game," Manfred said.

Shortly after that announcement, Houston owner Jim Crane conducted a news conference in which he confirmed Luhnow and Hinch had been dismissed.

"I'm going above and beyond MLB's penalty, today I have made the decision to dismiss A.J. Hinch and Jeff Luhnow," Crane told reporters.

"We need to move forward with a clean slate and the Astros will become a stronger organisation because of this today.

"You can be confident that we will always do the right thing and we will not have this happen on my watch."

MLB instigated an investigation following allegations from a report in The Athletic, which quoted Oakland Athletics pitcher Mike Fiers, who said Houston were using a camera positioned in the outfield to detect signs and relay them to hitters.

As well as suspending Luhnow and Hinch, former Astros assistant Brandon Taubman has also received a year-long ban from MLB. 

Taubman had been fired by the Astros in October following offensive comments he directed at a group of female reporters.