Maryland Gov. Martin O'Malley. (AP Photo/Patrick Semansky)

Gov. Martin O'Malley, Maryland's governor and a possible 2016 Democratic presidential contender, on Sunday defended the troubled rollout of his state's health care exchange.

"We squibbed the kickoff, but we’re making it better," he said on CNN's "State of the Union" Sunday morning, adding that the state has enrolled 180,000 people, more than half of its goal of 260,000. "This complex IT challenge had ups and downs at every step of the way," he said.

Senior officials in Maryland failed to heed warnings as much as a year ahead that the exchange's rollout was doomed, a Sunday report in The Washington Post revealed.

"The repeated warnings culminated days before the launch, with one from contractors testing the Web site that said it was 'extremely unstable' and another from an outside consultant that urged state officials not to let residents enroll in health plans because there was 'no clear picture' of what would happen when the exchange would turn on," the paper reports.

"That Web site is now functional for most citizens," he said.