The Adelaide City Council has agreed to install a rainbow walk in Light Square to celebrate the gay and lesbian community, despite receiving mostly negative and "abusive" feedback to the idea.

Rainbow colours will be painted on a walkway of the north western corner of Light Square, near Hindley Street as soon as funding has been sorted.

The council received more than 150 emails from the public in response to the idea, most of which were negative.

Deputy Lord Mayor Houssam Abiad said the vast majority of the emails were quite abusive and against the installation.

But that did not deter the council from supporting the move.

"Some of the messaging that was put in there was, 'What will I tell my children when they see a rainbow walk in the park in the city of Adelaide'," he said.

"If anything those negative emails have enforced the need for councils to act.

"[The councillors] have seen in those negativities an element of positivity where they felt that there was a minority group within our community that's not being supported and council has to play an active role in supporting that group."

Councillors were concerned funding might be an issue.

Mr Abiad said a report would look into funding options for the installation.

"To understand a little bit more about how potentially we could fund this, if this potentially may be a local government and community driven exercise where the community is also involved," he said.

"But these options will be explored at a later date."

The council has also voted to illuminate the town hall with LED lighting to celebrate the fortieth anniversary of decriminalising homosexuality in South Australia.

South Australia was the first state to pass those law reforms.