But they questioned whether all of those jobs truly represented the "critical needs" for which direct-hire authority is usually reserved.
"Please explain why there was a 'critical need' for HHS to waive provisions of federal hiring law to hire 90 dental officers to implement the health care law," they wrote.
The letter to OPM also says HHS would have had to hire 10 people per day to fill all of the positions OPM designated as critical.
"The pace of hiring that would be required for HHS to maximize this authority and fill each of those 'critical needs' is incredible," the lawmakers wrote.
In addition to Coburn, the letter questioning HHS's hiring authority was signed by Sens. Richard BurrRichard BurrTrump voter who cast ballot illegally won’t be charged Burr: US in new Cold War with Russia Senator: No signs of GOP 'slow-walking' Russia investigation MORE (R-N.C.), Michael Enzi (R-Wyo.), Charles GrassleyChuck GrassleyComey to testify before Senate Judiciary Committee GOP to kill language exempting staff from new ObamaCare repeal bill House cyber chairman wants to bolster workforce MORE (R-Iowa), Kelly AyotteKelly AyotteBottom Line How Gorsuch's confirmation shapes the next Supreme Court battle THE MEMO: Trump set to notch needed win with Gorsuch MORE (R-N.H.) and John ThuneJohn ThuneNet neutrality fight descends into trench warfare Hopes fade for using tax reform on infrastructure United explains passenger removal to senators MORE (R-S.D.).