The area is currently under a rāhui placed by local iwi Te Kawerau a Maki, and the council has since closed more than 40 tracks in an attempt to stop visitors spreading kauri dieback disease.
The post was later removed and an apology issued.
"Please be assured we are abundantly aware of the devastation kauri dieback disease is having on the park and we absolutely respect the significance of the rāhui and the measures Auckland Council is taking to stop the spread of this incurable disease," the apology read.
"There are still lots of places you can go walking in the bush [in] Auckland."
Te Kawerau a Maki executive manager Edward Ashby said he was not impressed by the error.
It was a symptom of a broader issue of mixed messages from the council, he said.
"A lot of the common questions are, or observations rather, are, 'Oh, there's a rāhui on but this track and that tracks open so we thought that was fine.
"So there's essentially council taking a track approach and we're taking a forest approach and the two apparently don't meet."
The iwi's stance had always been that the council was not doing enough by only partly closing off the park, Mr Ashby said.
However, there had been no meeting between the council and iwi over what message needed to be sent or received by the public and it was hurting the efforts to protect the park.
"There's are an awful lot of people that are not respecting the rāhui, that are entering the forest, and in fact there are still people entering currently closed tracks as well.
"So it's a social culture change, or behaviour change that needs to happen and that's very hard unless we have a very organised communications strategy."
In a statement, ATEED again apologised for the error, which it said was a scheduled post done by a third party agency that oversees the Facebook page.
It had taken steps to respect the rāhui, including stopping promotion of the Waitakere Ranges.
"We're not running any consumer marketing campaigns which promote 'walking in the Waitakere Ranges', instead promoting other elements in the west - for example the region's beaches and wine," it said.
"We have also stopped promoting the Waitakere Ranges via ATEED's managed social channels since the rāhui was put in place. These channels have also been used to share information on kauri dieback, and promote the rāhui."
Local councillor and Environment and Community committee head Penny Hulse said it was disappointing and all communications should support the rāhui.
"It's hugely challenging trying to get this into a very clear one-liner."
"Our clear position is we're asking people [to] respect the rāhui and to walk in other regional parks around Auckland and ideally stay away from any areas that have kauri in them.
"However, for us to formally close the park at the moment is not practical."
There would be a meeting with the iwi in the coming weeks and the council was set to get an update, including on measures under way with the government, later this month.
This article was originally published by RNZ.