A 220m-tall RNZ radio mast north of Porirua - the second-tallest structure in the country - was demolished this morning.

Live: Watch the mast fall here (video courtesy of Valley Audio):

The mast at Titahi Bay, which is second in height only to Auckland's Sky Tower, was designed to withstand a 1-in-2500-year storm, but was badly corroded.

The mast had already been cut back to 190 metres and just after 9am it was felled by explosives that severed the southern guy wires.

The mast fell to the north.

This audio is not downloadable due to copyright restrictions.

Some of the 150 people who gathered to watch the demolition of the radio mast, said they would miss seeing it out of their windows.

Ted Gallan has lived in Titahi Bay for 50 years.

"You know, you see a landmark come down, it's special. It's always been there, it's part of Titahi Bay, " he said.

Whitireia Park was closed to the public while the mast was brought down

The smaller of the three masts at the site was taken down in November.

Photo: RNZ / Matt Finn

Photo: RNZ / Matt Finn

Photo: RNZ / Matt Finn