"I think that he picked up momentum last week with the CPAC vote, with Maine, that will roll into Arizona and Michigan and then into Super Tuesday," Flake said on MSNBC Monday. "Obviously it's taken longer than a lot of us would like, but that's the process, and he'll be better able to handle the general."
Flake also defended Romney's conservative credentials, which came under question from prominent Republicans — including former vice presidential candidate Sarah Palin.
The Arizona congressman argued that traditional knocks on Romney's record — including his support for a state-wide healthcare mandate — were old news.
"This has been raised for years. To the extent that it's an issue, it's been an issue. I don't think it'll be an issue moving forward any more than it has been," Flake said.
Flake, an outspoken critic of government spending, also slammed President Obama's budget proposal, details of which were released over the weekend.
"I wish we'd actually have a real budget that takes into account the problems we have with entitlement programs and discretionary spending," Flake said.
Flake went on to argue that Congress should abandon the payroll tax cut, despite bipartisan support for its extension.
"We shouldn't be having a payroll tax cut, we shouldn't have done it a year ago. If we don't have the courage to reform the entitlement programs, we shouldn't be messing with the revenue stream," Flake said. "Republican or Democrat, we aren't serious enough about our deficit or debt."