Abu Dhabi on Sunday denied a claim by Iran-backed Huthi rebels that a missile fired from Yemen reached its air space or threatened a nuclear power plant set to open in 2018.

"The National Emergency Crisis and Disaster Management Authority denied claims by the Huthis in Yemen that they launched a missile today towards the airspace of the United Arab Emirates," the Emirati state news agency reported.

The authority sought to dampen fears that Abu Dhabi -- and specifically the Barakah nuclear plant -- was vulnerable to attack, saying the UAE "has an air defence system capable of dealing with any threat of any kind".

The Huthi rebels earlier Sunday claimed to have hit the Barakah plant, a "strategic target", with a cruise missile fired from Yemen.

In a statement broadcast by their news outlet Al-Masirah, the rebels said the attack followed a "successful" November 30 missile launch against Saudi Arabia, which along with the UAE is waging a military campaign against the Huthis.

Saudi Arabia said it had intercepted the missile but an earlier Huthi attack on November 4 threatened Riyadh international airport and prompted the Saudi-led coalition to tighten an already crippling blockade on Yemen.

The Huthis' latest claim came as their ally of three years, Yemen's former president Ali Abdullah Saleh, threatened to bypass the Iran-backed rebels and negotiate with the Saudi-led coalition.

The Huthis' political office accused Saleh of staging a "coup" against "an alliance he never believed in", and warned that Saudi Arabia and its allies -- which include the UAE -- would "pay a heavy price in their own capitals".