The Norwegian telecom group Telenor said it has prohibited the Chinese equipment maker ZTE from entering into tenders for six months. The operator said the Chinese firm had breached its code of conduct.
The exclusion period will end on 3 March. The ban covers all of Telenor companies and actives around the world.
ZTE has made no comment.
Telenor has come under pressure in Norway to reinforce its ethical standards after reports of poor working conditions and child labour practices at its subcontractors in Bangladesh.
Many of the longer established manufacturers have complained that Chinese companies - which are state-backed - are buying market share by undercutting on price to such an extent that they cannot compete.