It is understood a woman, who needed assistance at a wedding, unwittingly infected several people at a Wellington wedding. (File photo).

A cluster outbreak of coronavirus after a Wellington wedding shows how easy the virus is spread, a top microbiologist has warned.

This follows up to 12 people being infected at a wedding at Boomrock on March 14.

It has emerged a woman, who was unaware she was infected after travelling abroad, unwittingly spread the virus to several people at the gathering.

Stuff has been told that several people came into close contact with her after she became drunk and needed assistance off the dance floor.

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Earlier she had kissed a man, who tested positive a few days later.

The bride and groom at the wedding have declined to comment.

Microbiologist Dr Siouxsie Wiles said the Boomrock contagion incident illustrated the types of situations the lockdown measures were trying to eliminate.

While the cluster start occurred before the lockdown, Wiles said it was a "classic example" of the virus moving between individuals.

"It's one action of turning up [at a gathering] and starting up a chain reaction."

It was imperative that people stayed in their bubbles to limit the spread of illness, she said.

The Ministry of Health has confirmed 10 Covid-19 cases from the wedding and a further two probable cases.

It is one of seven Covid-19 clusters around New Zealand.

Boomrock's managing director, Ollie Ormond, said as a business it was continuously complying with all government and district health board (DHB) advice.

"As you can imagine we are all dealing with plenty at the moment so if you require further details please get in touch with the DHB in Wellington who have all the relevant information."

A Regional Public Health spokesman said it had been following up with the Covid-19 case associated with the event and was working closely with Boomrock.