WORLD Youth Day organisers have invited tens of thousands of Sydneysiders - not just Catholic pilgrims - to line the harbour foreshore and city streets to welcome Pope Benedict XVI as he moves about the city today.

The call comes as the Domain and parts of Hickson Road, which were initially set aside as an overflow venue for pilgrims who could not be contained in eastern Darling Harbour, were opened to the public. The Catholic Church said not all pilgrims expected had arrived.

The church coined today, the first official day of the Pope's five-day visit, Super Holy Thursday, and urged people to turn out to make "clear that Sydney welcomes the Holy Father, not just the pilgrims of the world".

"I really exhort through you anyone who can come to this spectacular papal arrival," World Youth Day's co-ordinator, Bishop Anthony Fisher, said. "Barangaroo will, I expect, be full of pilgrims but there are lots of other sites where people will be able to see the Holy Father's 'boat-a-cade', for instance, all along the foreshore along Circular Quay, and Woolloomooloo. The boat's going to come in nice and close so people can see the 'boat-a-cade' well. Those positions are intended for ordinary people, Sydney people, to come out."

The message was reinforced by the State Government which sensed the tourism opportunities of a spectacular welcome attended by an estimated 500,000 people. "In the same way the eyes of the world turned on Sydney during the Olympics, the Rugby World Cup and during every New Year's Eve, tomorrow Sydney will show everyone how a major event is done," said the Government's youth day spokeswoman, Kristina Keneally.

"I'm told television audiences of up to 1 billion people watched the Stations of the Cross at Toronto's World Youth Day."

But there was confusion about the extent of public access. The church at first had declared that all areas bar Barangaroo were open to the public.

"I wouldn't encourage the general public to try to get into Barangaroo," Bishop Fisher said. "They'd just be frustrated. But all those other sites are open to the general public. And we would encourage the general public to go there to those sites. We know that some of our pilgrims still haven't arrived. They are arriving later in the week. They're in other parts of Australia or from overseas. By the end of the week it will be very hard to even get into places like the Domain."

The World Youth Day Co-ordination Authority later confirmed that the Domain was open to the public but vantage points at Farm Cove and the Opera House were set aside for pilgrims and ticket holders only.

The papal tour begins with the arrival of the official flotilla of 13 boats, followed by up to 40 other vessels. The procession of boats will travel past Farm Cove, the Opera House, around Circular Quay, under the Harbour Bridge, to Walsh Bay and finish at the Hungry Mile where the Pope will be greeted by an estimated 140,000 pilgrims.

The Government said the best vantage points would be Mrs Macquaries Chair; and from East Circular Quay to the Harbour Bridge, Blues Point, Milsons Point, Kirribilli, Balmain and Pyrmont Point.

After the Pope addresses the pilgrims, the public will be able to see him as he tours the city in the official motorcade.

The best places to watch the afternoon road tour would be along George, Bridge, Loftus, Alfred and Macquarie streets.