Tensions reached a fiery climax on The Block, after two couples went head-to-head.

Tuesday night’s episode saw Sonny and Alicia accuse Han and Can of stealing their idea after both teams put a heated seat in their Hepburn Spa bathrooms.

In the challenge, the teams were told they could not include underfloor heating in their designs.

However, after doing some ‘out of the box’ thinking, House 4’s Sonny and Alicia fought hard to get heating for a seat approved, an idea they thought would win them the prize up for grabs: a state-of-the-art caravan.

However, after learning that House 2’s Han and Can had also inserted a heated seat in their space, all hell broke loose on site.

‘Why would you do that? If you’ve heard another house is doing it, why are you copying? It makes no sense,’ Alicia could be heard saying in a rant.

Tuesday night’s episode saw Sonny (left) and Alicia (right) accuse Han and Can of stealing their idea, after both teams put a heated seat in their Hepburn Spa bathrooms

However, after learning that House 2’s Han and Can (pictured) had also inserted a heated seat in their space, all hell broke loose on site

‘These girls better have a good excuse for this,’ she added, dubbing the move ‘uncreative’ and ‘unoriginal’.

When the couple went to confront Han about the alleged cheating, she denied that she and Can were guilty of any wrongdoing, claiming the chippies had let them in on the idea.

Sonny was livid over the conversation.

‘It’s just annoying because the legwork that I put in made it happen and that was our sort of secret, as such,’ he said to the camera.

‘We had a point of difference and now we don’t.’

Despite Han defending their decision to build a heated seat, Sonny and Alicia weren’t buying it.

‘When someone lies straight to your face, to me, that’s the worst. Just be honest,’ Alicia said in her piece to camera.

‘I think it’s full of s***. I think she heard our idea. I think they put no time into it.’

‘So you’ve got one person saying they’re innocent and you’ve got one apologising. So if you’re apologising, what are you apologising for if you’re innocent?’ Sonny said to the camera – a thought we were all thinking (Pictured: Han and Can)

Later on, Han could be seen filling Can in on the heated conversation, a moment that saw her break down into tears.

‘To be viewed as someone that would steal an idea, that absolutely disgusts me. I’m not that person,’ she told her partner.

Can later went to apologise to Sonny and Alicia, adding that the move wasn’t malicious but rather a misunderstanding.

However, the moment raised eyebrows both on site and on screens.

‘So you’ve got one person saying they’re innocent and you’ve got one apologising. So if you’re apologising, what are you apologising for if you’re innocent?’ Sonny said to the camera – a thought we were all thinking.

At dinner that evening, Han and Can arrived with a peace offering, revealing that if they win the caravan prize, they will give it to Sonny and Alicia.

But despite being an act of goodwill, the offer only made Sonny and Alicia more suspicious of the pair.

Later on, fuel was added to the fire as it came to light that Han had seen what Sonny and Alicia had done the night before at Hepburn Spa.

While it’s not clear if she lied or not, the mishap made Sonny and Alicia decide to up their game and hold their cards closer to their chest.