Ronaldo's Portugal captain's armband is put up for auction by charity

The captain's armband which Cristiano Ronaldo slammed to the ground after seeing what would have been a winning goal against Serbia wrongly disallowed was put up for auction on Tuesday.

A charity group, who are raising money to pay for the surgery of a six-month-old boy from Serbia with spinal muscular atrophy, were given the armband from a stadium worker who picked it up after the World Cup qualifier ended in a 2-2 draw on Saturday.

Ronaldo stormed off the field moments before the final whistle in Belgrade after his injury-time goal, which clearly crossed the line, was missed by officials.

The Juventus star was left furious after pouncing on a loose ball inside the penalty area and stabbing an effort towards goal, only to see Serbia defender Stefan Mitrovic clear the ball a second too late.

Replays showed the ball had clearly gone over the line but with no VAR in place, Ronaldo angrily protested before throwing his armband to the floor in disgust.

The former Real Madrid star was was publicly criticised for his behaviour and some believe his angry display could lead to FIFA sanctions if the governing body deems his reaction to be offensive or violent conduct.

However, the charity group hope the story around the armband will help them raise big money, with item available in an online auction for three days.

Afterward the incident, Ronaldo wrote on Instagram: 'Being captain of the Portugal national team is one of the greatest honours and privileges of my life.

'I give and will always give my all for my country, that will never change.

'But there are difficult moments to cope with, especially when we feel like an entire nation is being harmed. Head up and face the next challenge! Come on Portugal!'

Meanwhile, the referee at the centre of the controversy has revealed he apologised for an error of judgement after refusing to award Ronaldo's late strike.

Official Danny Makkelie was hounded by Portugal's players and management staff but he did not change his view that the ball had in fact not crossed the line.

'All I can say is that I apologised to the national coach, Mr. Fernando Santos, and to the Portuguese team for what happened,' Makkelie told Portuguese newspaper A Bola.

'As a refereeing team, we always work hard to make good decisions. When we are in the news this way, it does not make us happy at all.'