Barnaby Joyce was more than just member for New England, Deputy Prime Minister and Minister for Agriculture and (disastrously) Water. The New Zealander was also a member of various cabinet sub-committees. And one in particular: the National Security Committee.
Joyce was a member along with the PM, the Defence Minister, the Attorney-General, the Foreign Minister, the Immigration Minister and the Treasurer. As it turns out, Joyce shouldn't have been there; nor should he have been in Cabinet or even in parliament. As he admits he suspected, he was ineligible to be there under the constitution, because he was a Kiwi.