Over 11,000 workers from nine Pacific countries worked in New Zealand's horticulture and viticulture sectors last year under the Recognised Seasonal Employer (RSE) Scheme.
New Zealand recently announced it would increase the number of Pacific workers on the scheme to 12,850.
Amalgamated's national secretary Maurice Davis says they're trying to break down resistance to unions in the islands by explaining their role.
"We had a fair hearing from the minister from Samoa, Lautafi (Selafi) Purcell. He gave us time to talk. It was longer than the half hour we were given because they wanted to question us," Mr Davis said.
"I essentially wanted to give the message that we're the independent eye that's quite prepared to work with the companies in New Zealand."
Mr Davis said he would meet with a minister from another Pacific country on Tuesday.
RSE Scheme under review
New Zealand's Ministry of Business, Innovation and Employment is currently reviewing the RSE Scheme.
Mr Davis said he had an interview with the ministry's review team last week in which he conveyed the union's push for industry-wide labour standards in the horticulture and viticulture sectors.
The union was pushing this because there had been instances of worker exploitation, including heavy deductions on wages, he said.
"This is a privileged position for everyone but nobody more than the growers," Mr Davis explained.
"Without those workers, they would not be able to harvest their plants. So I don't see why they (Pacific workers) should come here incurring debt before they pick their first fruit, their first produce," he said.
"That's just crazy to me, that's nuts."
The ministry was effective at holding RSE employers to account if they were found to be exploiting workers, which complemented the union's role, Mr Davis said.
If the ministry found companies had abused their position in relation to the workers, then their accreditation as a RSE contractor was at risk, he said.
According to Mr Davis, some Pacific governments could be concerned about unionism emerging in their own countries while also being worried about exploitation of their workers abroad.
However, RSE workers have often been discouraged from joining a union by agents or brokers from their own countries, or employers themselves.
Meanwhile, Samoa's government has again asked the New Zealand government to increase the number of Pacific Islanders on its seasonal worker programme.
Over 2000 Samoans are now working in New Zealand under three separate employment initiatives.
The RSE scheme is by far the largest with 1800 Samoans working in horticulture and viticulture.