Protect Our Care, a major Obamacare advocacy group, is doubtful that outside spending can make up for a steep cut in ad funding for Obamacare outreach.

The group said during a press call Tuesday that it is meeting with other outside groups on what it can do to make up for a 90 percent cut to ad funding announced by the Trump administration last week. The administration plans to spend $10 million on ad funding for 2018 open enrollment, a 90 percent decline from the $100 million spent for the 2017 open enrollment period.

While Protect Our Care said it is working on a response, an official with the group said that it is very hard to make up for the cut.

"It is impossible to make up for what the administration is failing to do," said Leslie Dach, campaign chair for Protect Our Care and a former official at the Department of Health and Human Services under the Obama administration. "It is impossible to replace the funding and it is impossible to replace the system because the administration knows who is coming to visit the website and might need a nudge."

Dach said that the administration holds the "keys to communication and they made it clear they will keep those and not do anything to make the law work and actively undermine it."

The administration also cut funding for grants to navigators, nonprofits tasked with helping enroll people in Obamacare and pick plans and doctors, by nearly 40 percent.

HHS officials have said that the goal behind the cuts is to be more efficient. It also added that the public is more aware of Obamacare, which will have its fifth open enrollment starting on Nov. 1, and that more ad funding wasn't needed.