Sydney Opera House most expensive 'go green' attraction for St Patrick's Day

Sydney Opera House charges more to 'go green' on St Patrick's Day than any other of the world's most famous landmarks.

Around 150 buildings and monuments around the world went 'go green' as part of Tourism Ireland's 'Greenification of the World' initiative costing the tourist board €95,000 ($A13,220) in 2014.

The initiative, first launched six years ago, is designed to showcase Ireland's fun, scenery and heritage, and was spurred by Liam Neeson who, as a Hollywood A-lister and Irishman, put his voice to a Tourism Ireland film, urging everyone to 'go green' on St Patrick's Day.

The Opera House was the first to participate back in 2010, and in 2014 charged Tourism Ireland $A11,132.

The London Eye charged $9045 to illuminate. Other fees charged included: $4174 for the Sphinx and Pyramids in Egypt; $3576 for South Africa's Table Mountain; and $3310 for the Leaning Tower of Pisa in Italy.

Figures show that Irish landmarks cost disproportionately more to illuminate than international attractions.

However, a number of places went green for free, including The Empire State Building, Niagara Falls and the Las Vegas "Welcome" sign, as did Munich's Allianz Arena, Sleeping Beauty's Castle in Disneyland Paris, and the Taj Mahal Palace Hotel, among a host of other sites worldwide, according to Tourism Ireland.

Landmarks to go 'green' for the first time this year include Rome's Colosseum, Scotland's Edinburgh Castle and the top five floors of the Shard in London.

There is growing sentiment against the initiative, with many suggesting the greening 'stunt' is a waste of money.