Reopening the gates of the Phoenix Park to traffic will not go ahead as planned on Monday.
It has been pushed back to June 29 after consultation between the OPW and gardaí.
The gates have been shut since March as part of Covid-19 restrictions, apart from the Castleknock and Parkgate Street entrances.
Green party councillor Michael Pidgeon has been campaigning for through traffic to be banned from the green space.
Councillor Pidgeon said: "I think it's fantastic, I think it feels like a stay of execution for people who are using the smaller roads around the park.
"It's going to ensure that the routes where people have been walking, cycling, where kids have been learning how to cycle or people just enjoying the park, it's going to be a lot easier for them to do that."
Councillor Michael Pidgeon said it will make the park safer.
He added: "I think there's definitely an element of public pressure in it. There have been thousands of people using the park, and it's pretty clear that the OPW has seen that.
"The smaller roads are being used really, really well, but they are not being used by cars at the moment and they are being used by people going for a run and families cycling about."