New Zealand’s new government is considering creating a visa category to help relocate Pacific peoples displaced by climate change.

The new category would make official the Green party’s pre-election policy which promised 100 visas for those affected by climate change.

As part of the new Labour-led coalition government, the Green party leader James Shaw was given the role of climate change minister.

He told Radio New Zealand on Tuesday that “an experimental humanitarian visa category” could be implemented for people from the Pacific who are displaced by rising seas resulting from climate change.

“It is a piece of work that we intend to do in partnership with the Pacific islands,” Shaw said.

Before the election, the Greens also proposed increasing New Zealand’s overall refugee quota from 750 each year to 4,000 places over six years.

Shaw’s announcement comes after the New Zealand immigration and protection tribunal rejected two families from Tuvalu who applied to become refugees in New Zealand due to the impact of climate change.

The families argued rising sea levels, lack of access to clean and sanitary drinking water and Tuvalu’s high unemployment rate as reasons for seeking asylum.

The tribunal ruled they did not risk being persecuted by race, religion, nationality or by membership of a political or religious group under the 1951 refugee convention.

International environmental law expert Associate Professor Alberto Costi, of Victoria University, told the Guardian that the current convention could not accommodate environmental refugees. “The conditions are pretty strict and really apply to persecution. These people who arrive here hoping to seek asylum on environmental grounds are bound to be sent back to their home countries.”

In 2014 Ioane Teitiota, from Kiribati, made headlines after he applied in New Zealand to become the world’s first climate change refugee “on the basis of changes to his environment in Kiribati caused by sea level rise associated with climate change”.

The case was dismissed by New Zealand’s supreme court and Teitiota was deported the following year.

Costi acknowledged Shaw’s proposal would allow that gap in the refugee convention to be filled but said the problem would be legally determining whether an environmental migrant was still able to live in their home country.

“I have sympathy but legally it creates a big debate. There needs to be clear guidelines.”

Costi said there would be a difference in an application from someone from Tarawa in Kiribati, where conditions are obviously worsening every year, to those whose countries are only affected seasonally.

“It’s an idea to be explored. I would welcome more clarity.”