A majority of ASX top 20 companies will publicly advocate for an Indigenous Voice to parliament ahead of this year’s referendum, with corporate support outstripping campaigning in favour of same-sex marriage laws.

Describing the looming referendum as a chance to improve disadvantage faced by Aboriginal and Torres Strait Islander Australians through the proposed advisory body to government, companies including Wesfarmers, Coles and Telstra told The Australian Financial Review they would speak up in favour of a Yes vote.