Thousands at stake in auction to decide fate of Girls vs Boys.

Courtney MacKay will be without her biggest fan when The Block NZ: Girls vs Boys auction kicks off tonight.

MacKay's fiance, Highlanders' loose forward Joe Wheeler, will be on a plane to Japan to further his rugby career when the live auction is underway on TV3.

Wheeler lives with his interior designer girlfriend in Dunedin so he has plenty to gain if she and teammate Emma Diamond win.

The Super Rugby star has been supporting MacKay, 25, every step of the way but will miss out on the big finale on his way to Tokyo for six months with Japanese club Suntory.


"He did try to rearrange the flights so he could be with me but he is due to start with Suntory on Monday so it proved impossible," MacKay said.

"Joe is really gutted about missing the auction but he's a sports professional and it is all part of the job. His parents will be at the final cheering us on instead.

"If Emma and I win, I will be heading out to Tokyo for a bit to join Joe and experience a new culture."

After 11 weeks of DIY challenges, tears, tantrums and triumph, the four competing teams are finally on the back end of season five.

The teams were each tasked with renovating 1980s houses in the Auckland suburb of Meadowbank.

Real estate firm Barfoot and Thompson said the average price of a three-bedroom house in Meadowbank last month was $1.14 million.

Business development manager Sam Cable and his HR advisor mate Emmett Vallender, both from Wellington, packed in their jobs to make a go of it on The Block.

They are confident their gamble to win enough cash from the series to start a business or invest in property together will pay off.

"We have given up everything for this, and now we have nothing to lose," Vallender said. "We are getting to the business end of the competition now so naturally the nerves are starting to kick in a bit.

"But we have finished strongly and we are confident we will do well at auction."

The pair hit a rough patch when they were accused of cheating, after they were caught seeking advice from a design consultant.

"That was our fault and it was embarrassing," Vallender said. "We overstepped the mark but promised to make good for our mistake."

Friends Niki Osborne and Tiffany Mair have had their eyes firmly set on the main prize from day one.

Film and TV worker Mair has been preparing for the final by relaxing with family in Wanaka, where she lived before moving to Melbourne.

She said the worst moment on the show came when they decided to house a Siamese fighter fish in their final room.

The pair did not know they needed a heated tropical fish tank and they landed in hot water with animal lovers. "No one told us we needed special equipment so we took the fish back to the pet store," Mair said.

If the friends win, the profits will be split down the middle. "We would love to win but if we don't I hope the honour goes to Courtney and Emma as it would be good to see a female team lift the top prize."

On auction night, the teams keep the profit above reserve from the sale of their properties, plus the winning team takes home an extra prize of $100,000. Last year's winners of The Block, Christchurch couple Brooke Thompson and Mitch Davies, walked away with a profit of $290,000.

Burly builders Dylan Cossey and Dylan Guitink - known as Dyls and Dylz - have both been back working on a building site in Mt Maunganui in the run-up to tonight's live auction.

Guitink said if they won, he would buy a truck and some new tools and look at investing in his own home.

"It is still a very hot market in Auckland so it should go well," he said.

The Block NZ: Girls vs Boys live auction screens tonight, 7pm, TV3.