BHP Billiton and striking workers at its Escondida copper mine have resumed talks in an effort to reach a wage agreement, according to the Melbourne-based company.

"The good news is that we are back around the table and things are starting to come together in some form of a negotiation," chief executive officer Andrew Mackenzie said overnight in an interview with Bloomberg Television from the sidelines of the BMO mining conference in Florida. "Let's wait and see, and others I'm sure will update you on the progress of those talks."

A strike at Escondida, the world's biggest copper mine, halted output on February 9 after a month of talks failed to produce a wage accord. Union spokesman Carlos Allendes said on Sunday that no discussions were being held with management. He didn't immediately respond to requests for comment.

Disruptions at the Chilean mine, and a suspension of exports from Freeport-McMoRan's Grasberg in Indonesia, the second-largest copper mine, have spurred prices. A 27 per cent rally in the past year is emboldening workers at a time of surging earnings growth after companies made deep cost cuts when prices were low.

Mackenzie said the company is asking workers to approach issues of productivity and flexibility so that when ore grades decline in the future, the mine can continue to be profitable and provide jobs.

"The workforce at Escondida is already extremely well paid and I would be pretty certain that whatever the outcome of negotiations, they will remain reasonably to high paid."

The walkout by members of a union representing 2500 workers means BHP is reviewing its guidance for copper output of 1.62 million tonnes in the 12 months to June 30, including a forecast 1.07 million tonnes from Escondida. Stoppages at the operation will impact on Chile's economic growth, the country's Finance Minister Rodrigo Valdes said last week.

Rising demand, waning mine output and a lack of investment in new operations will push copper into the first deficit in six years, according to Citigroup. Prices may rise above $US8000 a tonne before the end of the decade, the bank forecasts. BHP sees a copper deficit emerging in the 2020s, while Glencore said last week it sees global supply of the metal declining this year.

"When you look forward, you don't have a prolonged deficit starting until 2020 but you can still get shortfalls," Mackenzie said, citing industry hiccups bringing new projects on stream in addition to larger issues like Escondida and Grasberg.

That said, it's "reasonable" to assume the strike gets settled and Freeport solves its problems at Grasberg, he added, in which case "that should more or less handle the supply out to 2020 but after that it's much more uncertain".