BMO Capital Markets said a presentation in Arequipa by the minister in which he claimed the country's copper output could grow 27% on last year's levels by 2022 implied about 3 million tonnes per annum of new copper production.

"Although new mines such as Quellaveco will boost output, we are significantly more cautious on project delivery and see about 2.5Mt as a more realistic 2022 level," the bank's analysts said.

"[This year] is struggling to see any growth.

"On the basis of the current project pipeline, we model Peru's output as peaking in 2024."

BMO said in a recent note Peru's copper output in the first half of 2019 was up about 2.7% year-on-year, but "still below the same period in 2017".

"The consistent 500,000tpa-plus growth rates seen over the 2015-16 period are very much in the past," it said.

BMO also said neighbour Chile, the world's biggest copper producer, was encountering similar "growth struggles".

"As the largest and second-largest copper producing countries in the world, trends in supply from Chile and Peru can have a major influence in market dynamics," it said.

"Chile has had a perennial problem with copper growth, despite sustained investment in new operations. [While] 2018 was a record year … helped by a strong recovery at the world's largest copper mine, Escondida,  disruptions have returned [in 2019] in the forms of Atacama rains and a Codelco labour disruption."