Compost company Living Earth is the Christchurch workplace linked to eight confirmed coronavirus cases.

The Ministry of Health released the information on Tuesday, back-tracking on advice issued on Monday that it would only be publicising information on clusters with 10 or more cases.

The ministry is investigating 14 clusters across the country, five of which originated in the South Island.

JOSEPH JOHNSON/STUFF Part of the Living Earth plant in Christchurch.

A Canterbury District Health Board (CDHB) spokeswoman said on Monday the eight confirmed and one probable case from Living Earth were all related to one "index case", who was a close contact of two staff.

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The index case had not travelled overseas, but was a close contact of a confirmed Covid-19 case – an overseas visitor who tested positive when they returned to their home country.

Living Earth, the composting facility in Bromley in east Christchurch, is owned by Waste Management and since 2009 has been contracted by Christchurch City Council to deal with its food and garden waste.

A council spokeswoman said they were aware of four cases of Covid-19 being identified at Living Earth, but not the others announced by the ministry.

A Waste Management spokesperson confirmed four Living Earth team members had tested positive for Covid-19.

"We are unaware of any other cases related to our site," they said.

The company had been working with the ministry and the CDHB since the first team member tested positive on March 22.

As soon as the first person tested positive, the company said it moved to identify close contacts, isolate the office area where they were based and have close contacts go into self-isolation.

"Six additional team members were identified by health authorities as symptomatic and were tested," the spokesperson said.

"Three were confirmed to have contracted Covid-19. Three team members returned a negative result."

All the Living Earth staff who had tested positive were recovering.

Asked to explain the discrepancy in numbers, a ministry spokesman said not all the Living Earth cluster cases were employees. The ministry was unable to provide further clarification on Tuesday.

Marist College, in Auckland, is the largest cluster in the country with 48 cases, followed by the World Hereford Conference, which took place in Queenstown. There have been 24 cases linked to the conference, five of which were confirmed on Tuesday.

Other clusters include weddings in Bluff (eight cases) and Wellington (11 cases), and a Hamilton rest home. Two separate clusters in Blenheim have 15 infections.