MEXICO CITY, Jan 29 (Reuters) - Mexico will review the auction process for government bonds, a finance ministry official said on Friday, following accusations of market manipulation and collusion in the secondary government bond market against seven major banks. Mexico would review the purchase options and how to make disclosure mechanisms more efficient in government auctions, Minister Gabriel Yorio said at a virtual news conference. “I believe that we have to reinforce the way in which the auctions are carried out by the Bank of Mexico,” Yorio said. “We are going to review it together with them.” The government has encouraged commercial banks to sign codes of conduct and could also create initiatives to reinforce governance within the banks to evaluate and monitor those codes of conduct, Yorio added. Mexico’s antitrust watchdog Cofece announced on Jan. 25 that it imposed fines totaling 35 million pesos ($1.75 million) on seven international banks and traders for market manipulation and collusion in the government bond market about a decade ago. Cofece said Barclays, Deutsche Bank, Santander, Banamex, Bank of America, BBVA Bancomer and JP Morgan as well as 11 traders agreed on 142 instances either to sell or buy bonds at a certain price or to not trade them at all. The trades were made between 2010 and 2013 and caused damage estimated to be worth 30 million pesos, it added. Santander denied wrongdoing and said it would appeal while BBVA Bancomer said it would analyze its next steps. The others declined to comment. (Reporting by Dave Graham and Cassandra Garrison Editing by Alistair Bell)