OSLO, June 8 (Reuters) - Norwegian business sector activity has accelerated during the past three months while the outlook for the next half year has brightened amid a gradual lifting of COVID-19 restrictions, a central bank business survey showed on Tuesday. “Contacts expect substantial output growth ahead as the measures ease through summer. Public building and infrastructure projects will amplify growth,” Norges Bank said. (Reporting by Terje Solsvik, editing by Gwladys Fouche) Our Standards: The Thomson Reuters Trust Principles.