From Factcheck.org:
This wildly inaccurate claim started as an inflated, partisan assertion that 16,500 new IRS employees might be required to administer the new law. That devolved quickly into a claim, made by some Republican lawmakers, that 16,500 IRS ‘agents’ would be required. Republican Rep. Ron Paul of Texas even claimed in a televised interview that all 16,500 would be carrying guns. None of those claims is true.
The IRS’ main job under the new law isn’t to enforce penalties. Its first task is to inform many small-business owners of a new tax credit that the new law grants them — starting this year — which will pay up to 35 percent of the employer’s contribution toward their workers’ health insurance. And in 2014 the IRS will also be administering additional subsidies — in the form of refundable tax credits — to help millions of low- and middle-income individuals buy health insurance.