By Teresa Cespedes

LIMA, May 19 (Reuters) - Doe Run Peru has told the government it will only meet the terms of a financial bailout plan if its deadline to complete an environmental cleanup plan is extended, one of its suppliers said on Tuesday.

The company's sprawling La Oroya smelter has been mostly stopped since March after banks, worried about falling metals prices, cut off its credit line in a sign the global downturn was hitting the backbone of Peru's economy.

In April, a group of mining companies that sell concentrates to Doe Run Peru agreed to give it a $175 million credit line if its parent company, U.S.-based Renco Group, met two conditions.

The stipulations were that Renco had to fill a $156 million financial shortfall in its Peruvian unit and pledge its shares to the Peruvian government as a way of promising that its unit would finish an environmental cleanup project of one of the world's most polluted sites.

But work at Peru's No. 4 exporter has yet to return to normal and company officials have told the government it wants its cleanup deadline extended before it puts its shares on the line.

"They are asking for an extension of the environmental remediation plan, among others things, that is what has frozen everything," said Ysaac Cruz, chief executive of mining company El Brocal (BRO.LM: Quote, Profile, Research)(BROi.LM: Quote, Profile, Research), told Reuters.

El Brocal was one of dozens of companies that sell concentrates to the smelter and agreed to back new credit lines for Doe Run Peru.

When it bought the smelter in a 1997 privatization auction, Doe Run was expected to take 10 years to clean up La Oroya. But in 2006 the company got a three-year extension and now the government is being asked to grant another one.