Charges against Alec Baldwin in Rust shooting set to be dropped.

Prosecutors plan to drop an involuntary manslaughter charge against Alec Baldwin in the fatal 2021 shooting of a cinematographer on the set of the film Rust, the actor's lawyers say.

"We are pleased with the decision to dismiss the case against Alec Baldwin and we encourage a proper investigation into the facts and circumstances of this tragic accident," Baldwin's lawyers Luke Nikas and Alex Spiro said in a statement.

Baldwin and the film's weapons supervisor, Hannah Gutierrez-Reed, were both charged with involuntary manslaughter in January.

The actor could have faced up to 18 months in prison if convicted. 

Baldwin was pointing a pistol at cinematographer Halyna Hutchins during a rehearsal when the gun when off, killing Hutchins and wounding director Joel Souza, in October 2021. 

Baldwin has said the gun went off accidentally and that he did not pull the trigger.

An FBI forensic report concluded the weapon could not have fired unless the trigger was pulled.

The case against Baldwin had already been diminishing.

A weapons charge, which would have meant a much longer sentence, had already been dismissed, and the first special prosecutor in the case resigned.

Meanwhile, it was confirmed filming is set to resume on set this week. 

Rust Move Productions lawyer Melina Spadone said via a representative that filming would restart on Thursday at the Yellowstone Film Ranch in Montana. 

Baldwin will continue his involvement as an actor and co-producer.

The production company finalised a settlement last month with New Mexico workplace safety regulars over "serious" violations, agreeing to a $US100,000 ($A148,945) fine to resolve a scathing safety review that detailed unheeded complaints and misfires on set before cinematographer Halyna Hutchins was shot and killed in October 2021.

Plans to resume filming were outlined last year by widower Matthew Hutchins in a proposed settlement to a wrongful death lawsuit that would make him an executive producer on a rebooted Rust.

More to come. 

- With AAP.

Feature Image: John Lamparski/Getty.