The tennis fan who brandished Russia's ultra-nationalist 'Z' war symbol at the Australian Open on Wednesday has returned to the Rod Laver Arena in a major security farce for tournament organisers.

There was uproar earlier this week when a male spectator was pictured wearing a black T-shirt with the white letter 'Z' emblazoned on the front. 

However, he was seen wearing the same 'Djokovic, Jordan, Messi' white T-shirt that he had worn over the black 'Z' T-shirt on Wednesday night. Security officials were seen speaking with the individual but decided to allow him to remain at the venue to watch Novak Djokovic cruise to a straight sets victory. 

Tennis Australia condemned the scenes witnessed during Novak Djokovic's quarter final clash with Andrey Rublev - in which a small group of fans waved flags printed with Vladimir Putin's face at Melbourne Park - but the same fan was spotted back at Rod Laver Arena for Djokovic's semi-final against Tommy Paul.

The letter 'Z' has become a symbol of ultra-nationalist obeisance to Russian president Vladimir Putin as he wages his war on Ukraine. It has been seen sprayed in white on the side of Russian tanks as they have invaded their neighbouring country.  

Organisers last week banned Russian and Belarusian flags from the venue for the duration of the tournament after one was held up at a match between Russian and Ukrainian players, while items of clothing that showcase a white letter 'Z' are among a list of prohibited items at the Australian Open.

Fresh questions will be asked of tournament organisers as to how such a security failure could occur, in a week where the event has been dominated by off-court geopolitical issues.

Djokovic's father, Srdjan, was filmed posing with supporters of Russian president Vladimir Putin outside Melbourne Park on Wednesday night. 

He opted to stay away from Rod Laver Arena on Friday so as not to distract from his son's match and maintains he had 'no intentions of being caught up in this.' 

Belarusian star Victoria Azarenka also shared a frosty exchange with a tennis reporter after her semi-final defeat by Russian-born Elena Rybakina, insisting that players should not be asked questions of a geopolitical nature.

'Whatever the answer I'm going to give it to you right now, it's going to be turned whichever way you want to turn it to,' she said. 

'So does it bother me? What bothers me is there's real things that's going on in the world. I don't know. Are you a politician? Are you? Are you covering politics?' 

The women's singles final will be played amid a tense political backdrop with Rybakina taking on Belarus' Arnya Sabalenka in Melbourne.