Fletcher held an event last week to celebrate the achievement with its staff.
Steven said he was initially taken back when the construction company contacted him.
"We were surprised when Fletcher Building contacted us as we hadn't thought to approach a construction company which shows even at the Rainbow Tick, we need to challenge our own stereotypes of what sort of organisations want to be inclusive."
He praised the company on its achievement, adding the company is now a welcoming workplace suitable for all New Zealanders.
Fletcher Building CEO Mark Adamson said his team worked hard to achieve this status.
"As the chairman of Fletcher Building's Diversity Council it makes me proud we have achieved this certification as it's an indication of the importance we place on diversity in our workplace."
ASB Bank, ANZ Banking Group, Westpac, Sky City, Sovereign Energy and Coca-Cola Amatil also hold 'Rainbow Tick' certifications.