American Vice-President Mike Pence has been welcomed by Prime Minister Malcolm Turnbull, who hailed his visit as a reflection of the importance the Trump government placed on relations with Australia.

The Vice-President arrived at Kirribilli House about 9am in an armoured black Cadillac bearing the American licence plate "800 002" and with a heavy security detail that included suited agents, uniformed soldiers and circling helicopters.

Security was tight for Mr Pence and his entourage, with a large police contingent patrolling the streets while police helicopters hovered overhead.

Sydney's famous Harbour Bridge was closed so Mr Pence's motorcade could make the short trip from his luxury hotel in the CBD to Kirribilli.