The Wicked Campers media statement, a rarity for the Australian company, joked it had employed monkeys to monitor the messages on the vans.
"[They are] a team of highly intelligent, socially conscious super monkeys to closely monitor the subject matter featured on our vehicles and scream loudly when offended."
The letter goes on to joke about now hiring seagulls and describes their legal team as three "crayon-wielding possums and one very good-looking banana".
Women's Refuge chief executive Dr Ang Jury said some messages on the vans were harmful and could retrigger victims of abuse.
"When you think this company cannot get any lower, this 'apology letter' makes it even more reprehensible," Dr Jury said. "These slogans are nothing but hate speech hidden as humour."
The company has long courted controversy in Australia and New Zealand with the messages, though rarely responds to media requests.
In the past the company said those offended should just paint over the messages they did not like. However, the statement said from now on the company would prosecute those who did that.