The Republican-led US state of Florida is expected to ban the teaching of sexual orientation and gender identity in all school grades, in an expansion of a controversial law the White House slammed as "completely, utterly wrong".

The move to expand restrictions on discussions of LGBTQ-related topics, dubbed by critics as the "Don't Say Gay" law, comes as Florida's Republican Governor Ron DeSantis lays the groundwork for a widely expected presidential run.

The new rule will be up for a vote by the Florida's Board of Education on 19 April, local media reported.

It has already been approved by the Department of Education, which like the board is led by DeSantis appointees, and will not need legislative approval to take effect, according to the reports.

If approved, teachers will be prohibited from "intentionally" teaching topics related to "sexual orientation or gender identity" to students from the fourth grade (fourth class) through to their final year of high school.

Last year's initiative applied only to kindergarten through third grade.

"Make no mistake: This is a part of a disturbing and dangerous trend that we're seeing across the country of legislations that are anti-LGBTQI+, anti-trans," said White House Press Secretary Karine Jean-Pierre.

Campaigners have launched a billboard campaign to oppose the 'Don't Say Gay' law

Mr DeSantis, who won re-election in 2022 in a landslide victory, has made battling politicians, teachers and businesses he accuses of wanting to impose a progressive "woke" ideology on others a central concern of his second term.

He has increasingly courted conservative voters with controversial proposals on education and immigration in recent months, as jockeying for the 2024 Republican presidential nomination heats up.

A rising star of the American right, Mr DeSantis is widely expected to go toe-to-toe with former president Donald Trump, who has already declared his candidacy.

The move to expand the "Don't Say Gay" restrictions has already drawn pushback from activists, including Equality Florida.

"This has been the goal all along: sweeping censorship and book banning targeting LGBTQ people in service to his presidential ambitions," the group tweeted, referring to Mr DeSantis.

"Now educators, in any grade level, and their livelihoods are being placed directly in the crosshairs for acknowledging that LGBTQ people exist."