New technology to light up rugby posts in different colours to show whether a kick is successful will be trialled at Cardiff's Principality Stadium.

Goal-light technology will be used for the first time in the UK at the Welsh Rugby Union's annual Judgement Day event on Saturday.

The Welsh company behind the technology hopes it could also revolutionise other sports such as American football.

However some fans have branded it a "waste of time".

Similar to how wickets light up in 20/20 cricket, some 500 LED lights on each rugby post are activated by remote control.

The light will show green if the penalty, conversion or drop goal was successful - or red if not.

It was successfully trialled earlier this month by World Rugby at the Hong Kong Sevens.

Inventor Michael Press, 33, said he believes the technology adds to the match-day experience of fans as well as aiding visually impaired spectators.

"Stadiums keep getting bigger and spectators are further away from the action so this technology is about giving everyone the same experience," he said.

"Stadiums are also changing, with giant screens, better seating, banners and entertainment, but no-one has changed things on the pitch."

A custom-made wrap - lined with the bulbs - fits around the posts and crossbar.

It will be used at the WRU's Judgement Day event where Cardiff Blues take on Ospreys after Scarlets face Dragons in the Guinness Pro14.

However there are no plans yet to use it again at the venue.

The company said the technology has also gained interest from other sports such as Gaelic football, hurling and rugby league.

"A lot of thought went into making the technology as simple as possible," said Mr Press.

"As soon as the touch judges raise their flags then we fire up the lights."

Mr Press is a former schoolmate of former British & Irish Lions and Wales rugby international Jamie Roberts.

However not everyone is convinced.

Some fans who responded to Roberts' tweet said the technology was unnecessary while others said it would help those with certain types of colour-blindness.