Qld Unions demonstrate for Yes campaign

Queensland Unions have thrown their support behind the "Yes" campaign in the marriage equality postal survey, with a major rally planned in Brisbane.

Union leaders and members will gather outside the Queensland Council of Unions building on Peel Street in South Brisbane on Friday morning to show their support for the "Yes" campaign.

QCU General Secretary Ros McLennan said the union movement had embraced the need for marriage equality.

"Queensland Unions are proud to stand with the 'yes' campaign because we know we don't get to pick and choose who gets equality and equality is union business," Ms McLennan said.

Residents have begun to receive their survey forms in the mail, but many have not and both the Yes and No campaigns are still hoping to get as many people on side as possible before they send their replies.

The union activity will run from 7:30am on Friday, targeting inner-city commuters with high-visibility rainbow flags.