"The reality is that we're not going to be critical of it because, as I say, it was a junior staff member who was very emotional."
The petition will not be put back up, he said – "what's done is done".
National campaigned strongly against the compact.
The petition, now deleted, said that the compact: "defers our immigration policies to the UN. It also restricts the ability of future Government to set immigration and foreign policy, and to decide which migrants are welcome and which aren't".
Bridges this morning said National's comments on the compact were "legal points around New Zealand determining its law."
"If you look at our immigration position, I think we have the strongest pro-migration position across the Parliament."
The man charged with murder after the terror attacks on Friday had posted pictures of his gun on social media with apparent references to the Migration Compact written on the firearm.
Bridges said National regularly archived petitions.
"I'm not involved in website maintenance – it's not something I give a moment's thought in my role as leader of the National Party."