"The Iraqi government welcomes an increase in support in weapons and training and (air) support from international partners in our war against Daesh," Abadi said in a statement, using an Arabic acronym for IS.
But "we confirm that Iraq has enough men and resolve to defeat Daesh and other similar criminal groups," he said.
Abadi's remarks came a day after American senators John McCain and Lindsey Graham advocated an increase in US forces in Iraq to around 10,000 from the current cap of 3,550.
And Graham, a member of the same committee, said: "I talked with the prime minister -- would you like more American help? The answer was yes."
He added: "If you went up to 10,000, you're not gonna get any pushback from the Iraqis.
"I mean the difference between 3,500 and 10,000 is meaningless politically inside the country."
The presence of American soldiers in Iraq, where the US fought a nearly nine-year war, remains a very sensitive issue, especially for politicians with close ties to Iran, who have a strong presence in parliament and the government.
Iraqi forces backed by US-led air strikes have since regained significant ground from the jihadists north of Baghdad, but large parts of the country's west remain under IS control.
