Manager of Opposition Business, I take your point of order. I referred to the Clerk and I've made my ruling. Manager of Opposition Business, I refer you to page 262 of House of Representatives Practice, 'Absence of a minister', which states:

It is of course desirable from the Government's point of view, and expected by Members, that there should be a Member present able to react with authority on behalf of the Government to any unexpected development.

While it's desirable, I have referred to the Clerk and I've made my ruling.