Elon Musk on Tuesday said he will move the headquarters of SpaceX and X to Texas after a California law blocked schools from forcing teachers to notify parents about changes to a student's gender identity.

"This is the final straw," Musk said on X a day after California governor Gavin Newsom signed the bill that fired up the already fraught culture wars in a tumultuous US election year.

"Because of this law and the many others that preceded it, attacking both families and companies, SpaceX will now move its HQ from Hawthorne, California, to Starbase, Texas," Musk said.

The multi-billionaire also said that he is transferring X, formerly Twitter, from its art-deco headquarters in San Francisco to Austin, a threat he has made before but never saw to completion.

"Have had enough of dodging gangs of violent drug addicts just to get in and out of the building," Musk wrote.

Musk has already moved Tesla's headquarters from Palo Alto in Silicon Valley to Austin, Texas, but still maintains an "engineering headquarters" in California.

The tycoon has expressed deep disdain for the use of preferred pronouns, often mocking the practice on social media and dismissing it as part of a "woke" agenda that was dangerous for society.

Musk is the father of a trans daughter from whom he is estranged, and he blames her California private school education for making her politically far left and turning her against him.

Newsom on Monday enacted the law after a contentious legislative process that pitted a handful of school boards fighting for parental rights against LGBTQ activists concerned about the welfare of vulnerable students.

The law reversed decisions in conservative school districts that ordered teachers to notify parents if a student changed their name or pronouns, or requested to use facilities or participate in programs that didn't match their official gender.

Newsom, who is seen as a potential alternative to President Joe Biden as the Democratic candidate for the White House, has often exchanged fire with conservatives over gender issues at state schools.

Last year, he signed a law that sets fines for school districts that ban textbooks portraying LGBTQ people and other marginalized groups.

Newsom also fought bitterly with a conservative school board over its opposition to the study of gay rights figure Harvey Milk, a San Francisco public official who was assassinated.

Musk has previously sparred with Newsom, who is a former San Francisco mayor, during the deadliest stages of the Covid-19 pandemic when he challenged the decisions of city and state health officials. (AFP)