It can be seen that whilst the legal provisions discussed above do regulate the manner in which the Governor-General may exercise his functions they still do leave considerable areas of discretion with him. These areas of nominal discretion have now been largely removed by conventional practice accepted and adhered to by the Crown and Governors-General. Thus it has been an accepted convention since 1856 that the Governor-General appoints as members of the Executive Council and as Ministers only those persons who are proposed to him by the acknowledged leader of the majority party in the House of Representatives; it is only if there is no party with a clear majority in the House, or if it has no acknowledged leader, that there is now any room for personal choice on the part of the Governor-General. Under the present circumstances of two-party government and selection of the party leader by caucus, the opportunity for this personal discretion does not arise, and has not arisen since 1928.

It is also an accepted convention that the Governor-General accepts and acts upon the advice of his Ministers in all matters, unless he has substantial reasons for knowing that the advice is not in accord with the majority of the House of Representatives or of the electors. At one time the Governor was loath to accept advice that might be prejudicial to British interests, but, since the Imperial Conference of 1926 at least, it has been accepted that the Governor-General always acts upon the advice of his Ministers except in the one case mentioned above. Since then, there has been no recorded instance of the Governor-General having specifically rejected the advice of his Ministers.

Even with respect to functions of an extra-legal and social nature, a conventional practice has been built up over the years, not so much, however, upon the advice of Ministers as upon the advice of the Governor-General's official staff. In these matters, of course, the Governor-General is freer to indulge his own judgments and tastes more extensively, but there are certain activities in which it is the practice for Governors-General to show their interest by their attendance or, in the case of certain national organisations, by accepting, when invited to do so, the office of patron.