Robbie Mortimer's rendition of the national anthem has gone viral ahead of State of Origin 1.

The country music star was tasked with getting proceedings underway just before the opening whistle but has copped a lot of criticism for his singing.

And it is fair to say that many watchers felt his effort was left wanting, with some even calling it the 'worst national anthem ever.' 

One user on X even compared his effort to Raygun's at the Olympics, writing, 'Robbie Mortimer competing for whatever gong Raygun won.'

Cade Lucas added, 'That is pound-for-pound the worst rendition of Advance Australia Fair I've ever heard. Surely Julie Anthony can be thawed out in time for game two.'

And it didn't stop there as Anthony Sharwood even suggested it was worse than hearing cats yowling, 'Two cats on heat were yowling in my backyard last night. They were more in tune than that,' they wrote.

Some think that the national anthem performance may actually be the worst thing that could happen today, writing, 'At least nothing that happens tonight will be worse than that national anthem.'

But there was early cause for concern that New South Wales may have turned in a worse performance, conceding a try inside 10 minutes.

The criticism of the national anthem wasn't just levelled at Mortimer's voice as some even took aim at the production.

'That’s gotta be one of the most overproduced anthems singings in Australia’s history right?' A user wrote.

'That is the strangest singing of the anthem I've ever heard,' another added.

On the field, the Queensland players seemed to be just as bemused by the national anthem.

A number could be seen with puzzled looks on their face as they tried to focus just ahead of kick off.