Issa requested a briefing with the two officials as well as written responses to earlier inquiries about the programs. He threatened to issue subpoenas if the department does not provide the information within the next two weeks.
Republicans have targeted the navigators program as part of a broader effort to undermine the healthcare law and the implementation effort.
Navigators will fulfill a role similar to traditional insurance agents, but can't be paid by insurance companies.
Navigators will likely come from organizations like community groups and churches. They will receive training about the healthcare law and help answer questions about new insurance options.
The Health Department has also announced a similar program for "assisters," who won't have to meet the same criteria as navigators.
Issa said department officials gave conflicting answers about whether grant money to help set up new insurance exchanges can be used for assisters. It can't be used for navigators, but one HHS official said that because assisters are different, the same restriction doesn't apply.
But Issa said HHS couldn't use the grants to pay for assisters, either, because the two programs are "essentially the same."