(Adds quotes, comments from ministers on flood impact)
By Mitra Taj
LIMA, March 22 (Reuters) - A railway used by copper, zinc and silver mines to transport concentrates from Peru's central Andes to port is likely be out of action for at least two to three weeks following deadly floods and mudslides, a minister said on Wednesday.
Repairs should take about two weeks, but work in the field was unlikely to start until next week once dangerous river levels had eased, transportation minister Martin Vizcarra told Reuters.
The railway has been closed since Friday, when torrential downpours triggered flooding and mudslides that killed at least 75 people and ruptured the rail line in several places.
"The damage wasn't mild, it was seriously damaged," Vizcarra said by phone. "It'll take at least two to three weeks."
Even after the railway resumes operations, exports from the port of Callao near Lima could be delayed by two to three weeks if ships wait for more concentrates to arrive in order to send full loads, said Deputy Mines Minister Ricardo Labo.
"It's going to depend on where stock levels are in Callao," Labo said.
The situation could put pressure global mineral prices.
Peru is the world's second biggest copper producer and third biggest zinc and silver producer. The railway usually transports about half of the country's zinc and silver output, about 60 percent of its lead production and about 10 percent of its copper output, according to the energy and mines ministry.
Vizcarra said the only available road routes took too long to be a practical alternative for transporting the minerals.
"That's why we have to make a strong effort to make the railway operative again," Vizcarra said.
Mines in central Peru, from Chinalco's Toromocho copper deposit to Buenaventura's polymetallic mine Brocal, have been stockpiling their concentrates while they wait for the railway to be fixed.
The recent round of heavy rains has prompted Peruvian miners Milpo and Volcan to declare force majeure and led Brazil's Votorantim to halt zinc smelting at its Cajamarquilla plant on the outskirts of Lima.
Labo said any impacts on production would be minimal or made up for later, since miners tend to use stoppages to undertake routine maintenance.
"So far no mine has halted production," Labo said. "That's the good news. And we don't believe they would stop production for another three weeks."
Mines could eventually be constrained by a lack of supplies, such as explosives or fuel, or storage space.
Warehouses at Callao have enough supplies to fulfill companies' commitments for up to 30 days, the country's mining association said Monday.
Reporting by Mitra Taj; Editing by Richard Pullin