TOPEKA ? Secretary of State Kris Kobach’s challenger in the Kansas Republican primary demanded Tuesday that Kobach fully disclose his earnings from outside work by releasing his income tax records for the past three years.

GOP challenger Scott Morgan said voters deserve to know the extent of Kobach’s financial dealings with private legal clients and other parties. Morgan said he believes Kobach is earning tens of thousands of dollars in outside compensation and contends many Kansas residents would be offended.

Kobach said he’s spent an average of fewer than five hours a week so far this year on outside legal business and Morgan can’t seriously argue that it’s a problem when previous secretaries of state also have had private, outside business interests.

Morgan, a Lawrence attorney, businessman and former local school board member, already has questioned whether Kobach focuses enough on the secretary of state’s duties. He said he’s willing to release his own tax returns if Kobach does.

Financial disclosure forms that Kobach has filed with the state show that since he took office in 2011, he’s received at least $2,000 in compensation from five private clients, as well as at least $6,000 from a law firm he’s maintained. But state law doesn’t require an official to disclose the exact amount, only whether the compensation was at least $2,000 during the previous year.

“You can’t have two professional jobs any more than you can have two spouses,” Morgan said during an interview after issuing a statement accusing Kobach of “cashing in with out-of-state clients.”

While Kobach said he won’t release his tax returns, he has calculated how much private legal work he’s done this year. Kobach said he billed his clients for fewer than 107 hours of legal work through May, or an average of 4.9 hours a week.

“Playing golf as slow as I do, that’s one round of golf,” he said.

The primary is Aug. 5 and will determine whether Kobach or Morgan faces Democrat and former state Sen. Jean Schodorf of Wichita, who also has questioned Kobach’s outside work.

Kobach faced such criticism even before he won his first four-year term in 2010. He’s nationally known for advising officials in other states on policies for cracking down on illegal immigration, and he helped draft tough laws for Arizona and Alabama. He’s also advised Kansas lawmakers on promoting gun rights, resisting the federal health care overhaul and challenging the federal government’s listing of the lesser prairie chicken as a threatened species.

Kobach said the outside work does not prevent him from ensuring that the office runs efficiently, citing efforts to keep its spending in check as an example. State documents show the office’s current operating budget of $5.3 million is about $607,000, or 10.3 percent, lower than it was four years ago.

He also noted that one of his predecessors, Republican Ron Thornburgh, owned a real estate firm, reported compensation from a coffee company in which he owned stock and served on the boards of several civic groups while in office.

“My predecessors owned or managed multiple businesses,” Kobach said.

Morgan said the issue is whether private clients have a claim on some of Kobach’s time and energy even though the state is paying him $86,000 a year as secretary of state.

“It’s not illegal,” he acknowledged. “It’s just not right.”