NEW YORK - Ms Tera Willis was backstage at the Metropolitan Opera, painstakingly adding strand after strand of salt-and-pepper hair to a half-finished wig - one of dozens she and her team were racing to finish in time for opening night later this month, after the pandemic had kept performers from getting measured until mid-August.

"I would love about six months," said Ms Willis, who is head of the company's wig and make-up department. "We have six weeks."

In the Met's underground rehearsal rooms, chorus members were straining to project through the masks they must rehearse in, a few pulling the fabric a couple of inches from their face for a moment or two. Just outside its gilded auditorium, which has been empty since the pandemic forced the opera house to close 11/2 years ago, stagehands were reupholstering some worn red velvet seats. Beneath the arched entry to the opera house, an electrician was installing wiring to make some of the heavy front doors touchless.

Reopening after the long shutdown was never going to be easy for the Metropolitan Opera, the largest performing arts company in the United States. Unlike a Broadway theatre, which must safely bring back one show, the Met, a US$300-million-a-year (S$403-million-a-year) operation, is planning to mount 196 performances of 22 operas this season, typically changing what is on its mammoth stage each night.

The stakes are high. The Met, which lost US$150 million in earned revenues during the pandemic, must now draw audiences back to its 3,800-seat opera house amid renewed concerns about the spread of the Delta variant.

Will people return in force, after getting out of the habit of spending nights at the opera? Will the Met's strict vaccine mandate - it will ban audience members younger than 12, who cannot yet be vaccinated - reassure operagoers, especially older ones? How much will travel bans hurt the box office, where international visitors made up as much as 20 per cent of ticket buyers?

The Met is warily watching sales. It has sold about US$20 million worth of tickets for the season so far, the company said, down from US$27 million at the same point in the season before the pandemic.

Subscriptions, which have been steadily eroding at American symphony orchestras and opera companies in recent years, are down by about one-quarter from before the pandemic, but officials expect more subscribers to renew when they feel safe about attending.

Strong recent sales and the speed with which the Met sold out an affordably priced performance of Verdi's Requiem last Saturday to commemorate the 20th anniversary of the Sept 11 attacks offered hope that audiences will come back.

The financial uncertainty led the Met to seek concessions from its unions, some of which will be restored if and when the box office approaches pre-pandemic levels. The ensuing labour disputes further complicated the reopening. The company did not reach a deal with its stagehands until July, delaying summer technical rehearsals, and only settled another, with its orchestra, late last month.

So now, the company is gearing up quickly, preparing to marshal the forces of about 1,000 singers, orchestra players, conductors, dancers and actors scheduled to perform this season.

It started with two free performances of Mahler's Symphony No. 2 "Resurrection" outdoors at Lincoln Centre last weekend; will perform Verdi's Requiem on Saturday, its first performance back inside the opera house, a concert that will be broadcast on PBS; and it will finally open the opera season on Sept 27 with Terence Blanchard's Fire Shut Up In My Bones, its first opera by a black composer. The company is hoping that Fire and another contemporary opera - Eurydice by Matthew Aucoin - will draw new audiences.

The whole organisation is getting ready to reopen. Mr Keith Narkon, a ticket seller, was with his colleagues behind the Met's box-office windows, stuffing tickets into envelopes and happy to be back after the virus had taken away their jobs for more than a year. "It was just this numbness," he said of the long shutdown.

As the opera house buzzes with pre-season anticipation, there are still bruised feelings from the labour battles, but there is also a palpable sense of relief. "You don't realise how much you respect the job until you don't have it," said Mr Phillip Smith, a stagehand who has worked at the Met for more than 20 years.

But life backstage is far from normal as company officials keep a close eye on the steps they must take to keep the company and the audience safe.

A special patron's entrance area has been turned into a testing centre, where those in rehearsals must get saliva collection tests twice a week. The first two rows of seats in the auditorium will be blocked off until the end of the year.

"On one hand, it's frightening and frustrating to see the rate of infection," said Mr Peter Gelb, general manager of the Met. "But it's so thrilling to see the possibility within grasp of actually opening performances."

Some bitterness lingers over the labour disputes, which were resolved when the company's three biggest unions agreed to new contracts that cut their pay modestly, saving the company money by moving some workers to a different healthcare plan and reducing the number of guaranteed full-time members of the orchestra and chorus.

To reopen smoothly, the Met's employees still have numerous battles to wage.

Everything from fabrics for costumes to machinery for stage lights to basic materials such as plywood and steel are proving difficult to obtain because of pandemic supply chain problems. And booking the international performers that opera relies on has become a mess of unpredictable red tape, between visa troubles and virus-related travel restrictions.

One of the few times performers can take off their masks these days is when they are being fitted in the costume shop, for photos that are taken to help designers take in the effect of each costume.

"If there's an unspoken feeling, normally I would be able to see that on a performer's face, but I can't access that," said Mr Paul Tazewell, the Tony-winning costume designer for Fire. But come Sept 27 - if everything goes as planned - the masks will come off, the Sputnik chandeliers will ascend, the curtain will go up and live opera will be back on stage.