The visit is part of a programme Mr McClay has put together by working with the tourism and business sector.
To start the day the group were given an official pohiri onto the Rotowhio marae at Te Puia, the New Zealand Maori Arts and Crafts Institute, by kapa haka group Mauri Oho.
They then moved inside the marae where a representative from Te Puia welcomed the group.
Te Puia chief executive Tim Cossar spoke to the delegates saying the organisation received a lot of visitors, and also had members of staff from the visiting delegates' nations.
He told the group about the history of the not-for-profit organisation and its plans for the future, including a new restaurant and schools' facility.
Mr McClay responded with a speech where he spoke of the visitors as "important friends of New Zealand and Rotorua".
"They have a very special relationship with New Zealand, not just of trade here and at home, but of a common language of friendship."
Mr McClay said he was grateful for the delegates for being here "to take a look at this special corner of New Zealand".
After the welcoming ceremony the High Commissioner of the Republic of Singapore, Bernard Baker, said he was excited and happy to be in Rotorua.
He said with Singapore Airlines flying to Wellington Rotorua should expect more Singaporean tourists.
"They love the natural beauty, the space and the weather. They love visiting New Zealand."
The trade commissioner from Vietnam, Kam Nguyen, said she had enjoyed the pohiri.
"It will be a good day to see the business industry in Rotorua, as well as visiting the timber mill, tourism and education areas."