Set in the heart of the world's largest tropical rainforest, the Arena Amazonia stadium looms white and majestic over the state capital Manaus.

The lozenge shape of a venue that dreams of being Manaus' sporting answer to its spectacular opera house symbolises the region's iconic straw baskets.

Yet after the World Cup circus has moved on, the building could end up being an expensive white elephant.

"We are building, in the middle of the Amazon rainforest, a new 21st Century opera for sport," architect and project coordinator Miguel Capobiango Neto told AFP.

The comment refers to the legendary Manaus Opera built in the jungle itself by rubber barons in the late 19th century. Its constituent parts were brought over all the way from England by boat.

Now the stadium is looking to become another famous local landmark.

"Today, this 6,670-ton metallic structure has come over in three parts from Portugal to build this fine 44,000 capacity stadium," said Capobiango.

The stadium design is striking. It's transparent roof captures rainwater via seven 120-litre reservoirs. And it will be the first construction in northern Brazil to obtain a green sustainability certificate.

Builders broke ground at the venue in July 2010 and the Arena should be completed on December 20, just in time to meet a strict FIFA deadline of December 31.

However, temporary installations will be completed "a little later," say the Manaus team.

Currently, 1,900 construction workers are beavering away at the site as the clock ticks down.

Yet to be installed as of this week were the seats, "all in the colours of regional fruits," said Capobiango.

By the time the venue is complete, 5,500 workers will have been involved in a project costing 595 million reais ($257 million, 189 million euros), the architect noted.

And after the World Cup?

The Arena will host four matches during the World Cup.

But thereafter it is not slated to see any top class football action -- not least as, despite Manaus being a city of two million people, it does not have a top flight football team.

Nor do fellow venues Brasilia, Natal or Cuiaba.

Football in the region is mired in financial crisis and any local players who do make the grade swiftly move on to bigger clubs, causing some fans to stay away.

Ironically, Manaus hosts the "Peladao" championship -- the largest amateur league in the world.

"That is much more popular" with locals than regional league action, asserted Capobiango.

The parlous state of the local game in the region has prompted concern that the new stadium will become a "white elephant" after the World Cup.

Many locals wonder why public money was poured into the project when Manaus lacks infrastructure in terms of quality schools and hospitals.

"They have spent millions when people are short of so much; they are hungry and dying in hospital doorways.

"And we won't even be able to afford to go to the stadium," complained local trader Vanilde Basto.

"They would have done better to invest in culture," said student Sheila Juliane, who noted that most of Manaus' cultural offerings are free.

Printer Thago Barreto said the Brazilian league must invite top clubs to play at the Arena.

"After the World Cup they will have to bring the Brazilian championship here or else it will be an empty shell," Barreto warned.

Locals also are angry about the "privatisation of public space" in that, after the tournament, the stadium concession will be handed over to the private sector.

Yet 70-year-old Peladao coordinator Arnaldo Santos said the criticism is short-sighted.

"The stadium was constructed for big events and serves above all the development of the whole region.

"The World Cup makes football visible and Manaus profits from that."

Even so, to be viable the stadium will have to generate sufficient revenue to pay for its upkeep, costing an estimated $215,000 a month.

To stave off criticism they may be creating a white elephant, authorities in Manaus have considered all kinds of post-World Cup plans -- even converting the venue into a detention center.

But Capobiango is optimistic.

"The Arena will host other shows and international events. It is a tourist site that will attract new investment for industry and tourism.

"It will be white -- but not a white elephant," he insisted.