LONDON (Reuters) - The United States, France and major economies are unlikely to halt the rises in their debt levels in the next few years, credit rating firm S&P Global warned on Tuesday.

The assessment comes ahead of upcoming elections in the U.S., Britain and France where governments are pledging to improve economies, social services and voters' daily lives.

"We estimate that --for the U.S., Italy, and France-- the primary balance would have to improve by more than 2% of GDP cumulatively for their debt to stabilize; this is unlikely to happen over the next three years," S&P said in a report.

"In our view, only a sharp deterioration of borrowing conditions could persuade G7 governments to implement more resolute budgetary consolidation at the present stage in their electoral cycles."

(Reporting by Marc Jones; Editing by Dhara Ranasinghe)