(Adds detail on maintenance of second auction, adjustment to mechanism)
MEXICO CITY, July 30 (Reuters) - Mexico's currency commission said on Thursday it would raise the sum sold in daily auctions to $200 million from $52 million to reduce the risk of volatility in the local foreign exchange market.
The $52 million auctions were started in March to support the peso currency, which has hit a series of record lows against the dollar in recent weeks.
The new rules would for now apply from July 31 to Sept. 30, the currency commission said in a statement.
The commission, which comprises the central bank and finance ministry, said it would maintain a separate daily offer to auction $200 million, which was triggered for the third time earlier on Thursday since it was first announced in December.
However, as of Friday, instead of being triggered by a 1.5 percent fall in the peso, the auction would now be activated by a 1 percent decline, the commission said.
The commission said it would reevaluate both measures at the end of September. (Reporting by Jean Luis Arce and Noe Torres; Editing by Meredith Mazzilli)