MIAMI, USA (AFP) — Mitt Romney's senior campaign adviser in Florida hinted yesterday that the Republican presidential challenger lost the state, where a result was still to be declared two days after the election.

President Barack Obama ended up not needing the biggest swing state as he romped to a decisive electoral college victory on Tuesday night.

A statement from Romney's Florida campaign published in the Miami Herald suggested his team had already accepted defeat.

"The numbers in Florida show this was winnable. We thought based on our polling and range of organisation that we had done what we needed to win," senior campaign adviser Brett Doster said in the statement.

"Obviously, we didn't, and for that I and every other operative in Florida has a sick feeling that we left something on the table," he said.

Obama campaign manager Jim Messina said he was confident the president would be declared the victor.

"Sometime today (Thursday) we think we will officially be the winner in Florida," Messina said.

The campaign's voter model continues to show that Obama "will hold that lead and end with 332 electoral votes," Messina said.

In the state-by-state electoral college system, 270 votes were needed for victory and Obama already has 303 with Florida's 29 still outstanding.

Votes are still being counted in three of Florida's 67 counties, said Chris Cate, a spokesman for the state government. "Counties are required to report their results to us by Saturday at noon," Cate told AFP.