About 120,000 sausages and 1500 litres of tomato sauce will be served at the Queen's Big Aussie Barbecue in Perth later this month.

Tens of thousands of West Australians are expected to crowd Perth Foreshore to share a snag with Queen Elizabeth II and Prince Philip on October 29, in what Premier Colin Barnett said would be an internationally historic event.

The Queen and the Duke of Edinburgh will take part in a traditional Aussie barbecue when thye touch down in Perth for CHOGM. Credit:AFP

The royal couple will travel in a slow motorcade before stepping out to "mingle" with families, albeit behind a roped off path.

At least $250,000 is expected to be raised from gold coin donations for the sausage sizzle.