* 2021 GDP outlook raised to between -0.5% to +1%

* 2021 exports seen up 12-14% vs 10-12% seen earlier

* Easing of curbs starts Wednesday

* Says economy may grow 6% next year (Releads, adds details throughout)

BANGKOK, Sept 1 (Reuters) - Thailand's leading joint-business group on Wednesday raised its 2021 economic forecast to between a 0.5% fall and 1% growth, after a relaxation of containment measures and signs the country's biggest wave of coronavirus infections was easing.

The restrictions in Bangkok and other provinces will be eased https://www.reuters.com/article/idUSL1N2Q006L from Wednesday, allowing more travel and activity to resume as Thailand tries to revive its flagging economy https://www.reuters.com/article/idUSL4N2PL05N while dealing with the outbreak and ramping up vaccinations.

The group's outlook upgrade was the first time this year following August's downgraded estimate of between a 1.5% drop and 0% growth of 2021 gross domestic product, according to the joint group of industry, banking and commerce.

The easing of curbs should lower an economic loss to between 200 billion baht to 300 billion baht ($6.2 billion to $9.3 billion) this month, down from 300 billion baht to 400 billion baht projected earlier, the group said.

"Last month we didn't get the picture and had no confidence in vaccine procurement which could lead to longer lockdown measures," group chairman Payong Srivanich told a briefing.

"But today we believe in the government's (vaccine) figures... and that infection numbers have peaked."

Thailand on Wednesday reported 14,802 new infections, after reaching as high as 23,418 on Aug. 13.

The group also raised its export outlook to a rise of 12-14% this year, up from 10-12% predicted earlier.

For 2022, Southeast Asia's second-largest economy could grow 6% if the country can fully reopen to foreign visitors by December and its vaccination plans are on track, Supant Mongkolsuthree, chairman of the Federation of Thai Industries, told the briefing. ($1 = 32.27 baht) (Reporting by Orathai Sriring, Satawasin Staporncharnchai and Kitiphong Thaichareon Editing by Ed Davies, Martin Petty)