SINGAPORE, Nov 26 (Reuters) - Singapore"s DBS Group (DBSM.SI) said its online banking services had been fully restored after suffering disruptions for about two days in its biggest outage since 2010, prompting the central bank to consider taking supervisory action. In a Facebook post late on Thursday, Southeast Asia"s biggest lender said customer logins and transaction activities have returned to normal pre-disruption levels since Thursday morning. The bank"s services, including its payment app, were disrupted on Tuesday and Wednesday. DBS said its systems remain secure and were not a target of a cyber-attack. "We will continue to monitor and review the events of this week and are taking steps to prevent future recurrences," the bank said.The disruption drew the ire of thousands of customers just hours after the bank, Singapore"s largest, announced a fix after the first day of the outage on Tuesday.