State officials are trying to involuntarily transfer the sheriff’s lieutenant overseeing law enforcement at Daniel K. Inouye International Airport, according to two sources with knowledge of the situation.

Attempts to switch Lt. Michael Oakland, who most recently served as the sheriffs’ Airports Patrol Section commander, to the Kapolei Courthouse come amid uncertainty over the deputy sheriffs’ future role at the airport.

“My understanding is they’re checking to see whether it’s legal or possible (to transfer Oakland) just on his position as a union employee,” state Sen. Will Espero (D, Ewa Beach-­Iroquois Point) said Monday. “I know it’s being questioned or challenged.”

Oakland has been with the state’s Sheriff Division nearly 18 years, and he also serves as Oahu chairman for Unit 14 in the Hawaii Government Employees Association, representing state law enforcement and ocean safety officers, according to his profile on the career website LinkedIn and the HGEA website.

Some critics, including Espero, have questioned whether the state Department of Transportation aims to end the deputy sheriffs’ airport presence as payback for a lawsuit filed by the sheriffs union to block the state’s new contract with a private airport security firm.

DOT officials recently gave the Department of Public Safety 180 days’ notice to end its 15-year-old contract with the sheriffs, who oversee law enforcement there, as the private company Securitas has played an expanding role in providing security services for the airport.

Last week DOT Director Ford Fuchigami held a news conference to say he aims to keep the 57 deputy sheriffs who work at the airport if they can reach a new deal in that time frame.

Both DOT and the HGEA referred inquiries on the matter to DPS.

In an emailed response Monday to phone messages regarding Oakland’s status, DPS said it made multiple “command reassignments” in June — at its Executive Protection Unit, Circuit Court, Kapolei Court, Records Section and Airport Section.

“I believe all of these individuals are accomplished leaders and these moves will strengthen and benefit our Sheriff Division as we move forward,” Public Safety Director Nolan Espinda said in a statement.

Espero, meanwhile, said he “definitely” has concerns that the effort to transfer Oakland stems from the union’s attempts to block Securitas’ three-year contract at the airport, worth a reported $35 million a year.

Oakland did not respond to requests for comment.

Honolulu Star-Advertiser reporter Gordon Y.K. Pang contributed to this story.