Scott Morrison faces stiff opposition on plans to allow vaccinated Australians to travel between states in the event of coronavirus lockdowns. The prime minister will pitch his internal passport idea to the national cabinet later this week. But the proposal would deny freedom of movement to the many Australians who refuse to be immunised. Cabinet minister Simon Birmingham said the plan would give Australians greater certainty in terms of what benefits being vaccinated delivers for them. But premiers and chief ministers are not sold on the interstate passports, and neither is federal backbencher Matt Canavan, who says freedom of movement is an Australian birthright. “First and foremost, I want to make sure we keep the borders open by keeping COVID-19 suppressed,” Senator Birmingham told ABC radio on Monday. “That is the priority, to make sure the states and territories have no excuse or reason to close those borders. “It’s not …