Organisers of a controversial campaign to get pro-atheism ads on buses say they may go to the Human Rights Review Tribunal after transport company NZ Bus backtracked on plans to allow the ads.
The Atheist Bus Campaign last year raised more than $22,000 to fund the ads, which created a storm when they ran in the United Kingdom, Canada, Germany, and Spain.
The ads read, "There's probably no God. Now stop worrying and enjoy your life".
Similar campaigns have run in Australia, the United States and several European countries.
NZ Bus tentatively approved the ads for buses in major centres, but later backtracked after receiving a number of complaints from the public and staff.
The company has defended the decision, saying it has the right to decline ads that it sees as controversial or divisive.
Campaign spokesman Simon Fisher said NZ Bus had double standards, given that religious ads were regularly allowed on buses.
"It's really disappointing. It does seem to show that there is a bit of a double standard out there when it comes to ads like this," he told NZPA.
"It needs to be out there in public. We need to get people in the street to stop and look and think about what they believe, and why they believe these things."
Campaign organisers had tried to reach a compromise with NZ Bus and invited staff to mediation sessions through the Human Rights Commission, but the company declined, Mr Fisher said.
"Putting up that wall between us didn't allow us to have any sort of discussion, any dialogue about how we could allay their fears, how we could possibly change the content of the ad, or how we could get around it being so controversial - even though I'm not sure it could be less controversial," he said.
"They were fixed in their ideas and they didn't want to hear what we said, and they basically said that 'whatever you say won't change our minds'."
The group was considering taking the case to the Human Rights Review Tribunal, Mr Fisher said.
Donations would not be used to pay legal costs, so organisers were considering whether to apply for legal aid through the tribunal's review board.
"The decision there is basically whether or not it's going to be worth our time."
Another option would be to run the ads in other highly-visible public advertising spaces, such as billboards or bus shelters, Mr Fisher said.
NZ Bus spokeswoman Siobhan O'Donovan said the campaign had drawn a "significant reaction" from passengers and staff, with a number finding it distasteful or distressing.
"NZ Bus has the right to decline advertising that may, in its perception, be considered controversial or divisive," she said.
"We have said 'no thank you' to Mr Fisher and have wished him well in his endeavours to secure a bus company to work with."