Thousands of people – including a singing policeman – have gathered in New Zealand to protest against a proposed housing development on land seen as sacred to the Maori people, despite efforts by Prime Minister Jacinda Ardern to calm the dispute.

The country’s largest builder, Fletcher Building, plans to develop 480 houses in the city of Auckland, on the Ihumatao Peninsula near its airport, on land that borders an important archaeological site and is seen as culturally significant.

The company last week sent eviction notices to a group that has occupied the land for several years to try to halt the development, sparking what is now six days of protests and a groundswell of opposition on social media.

Ms Ardern entered the row on Friday, saying there would be no building on the land until the dispute could be resolved.

She promised talks would include people occupying the land.

She had faced criticism for not stepping in earlier, despite Maori leaders in her party coming out in support of the protest movement.

While her entry into the debate reassured the crowd occupying the site, it was the melodious voice and lilting guitar of an unnamed police officer many will remember as the greatest influence in calming tempers.

When this officer took up a guitar and launched into a gentle lullaby, even hardline protesters were moved.

The dispute presents a challenge for Ms Ardern’s popular Labour government before an election next year as it looks to juggle the urgent need for more affordable housing against the demands of its Maori supporters.

The project’s supporters argue that it will provide new homes in the country’s largest city. House prices have nearly doubled in the past decade.

The protesters, led by a Maori group called Save Our Unique Landscape (SOUL), however, say the area has historical, cultural and archaeological significance and should be left as an open space, or returned to the indigenous people.

An estimated 5000 people gathered at the site on Saturday, according to Radio New Zealand, putting up more than 50 tents.

Protests were also held in other cities.

-with AAP