"Obamacare has to be repealed and replaced and it has to be replaced with something much less expensive for the people, otherwise this country is in even bigger trouble than everybody thought," the Republican presidential candidate said at his golf course in Doral, Florida.
"We're going to repeal and replace Obamacare."
The Department of Health and Human Services said in a new report the big increase in insurance costs will be seen in the 38 states with federally-managed health care exchanges set up under the Affordable Care Act (ACA).
It is the largest jump in premiums for the program, now entering its fourth year, and stoked the already-heated battle between Trump and Democratic rival Hillary Clinton to replace Obama in the White House.
Trump quickly lashed out on Twitter following the report: "#Obamacare premiums are about to SKYROCKET --- again. Crooked H will only make it worse. We will repeal & replace!"
Clinton's campaign hit back at Trump saying he wants to "rip up the ACA and reverse the progress we have made."
Trump would "throw 20 million people off their coverage and let the insurance companies write the rules again," campaign spokesperson Julie Wood said. "Hillary Clinton wants to build on the progress we've made and fix what's broken."
Republicans repeatedly have tried to overturn Obamacare, which has allowed millions of uninsured people to get health insurance, with no limits based on "pre-existing conditions." The program has reduced the number of individuals across the country without insurance to 8.6 percent from 16 percent in 2010, HHS said.
Despite the sharp premium increase, HHS said most consumers will see rate hikes below the average amount due to premium caps and subsidies for those with lower incomes.
Speaking in Florida, Trump disputed the government's figures, saying insurance costs are rising much higher.
"Obamacare is just blowing up and even the White House, our president, announced 25 or 26 percent (increases). That number is so wrong. That is such a phony number. You're talking about 60, 70, 80 percent in increases, not 25 percent," Trump said, without explaining where he got his numbers.
Trump said the increase for Texas will be 60 percent, but the HHS report said premiums in that state are expected to increase by an average of just 18 percent.
'Unsustainable system'
However, Arizona -- which has not voted for a Democrat for president since Bill Clinton in 1996 -- will see eye-popping 116 percent increases.
Arizona Senator John McCain, a Republican, said: "As I have long warned, Obamacare is an unsustainable system that places an unfair financial burden on families and small businesses."
And McCain said the state's largest county has only one insurance provider under Obamacare, when the health care exchanges were supposed to create competition and provide individuals with a choice of insurers.
Republican House Speaker Paul Ryan compared Obama's healthcare program to ill-fated and now-discontinued Samsung phones that were catching fire.
"The president recently compared Obamacare to a Samsung Galaxy Note 7, and he's right: this disastrous law is blowing up. But at least you can return the phone," Ryan said in a statement.
