Dodgy joinery seems to be proving little deterrent to charity-auction bidders for the children's playhouses knocked together in three hours by contestants of The Block NZ.

All four of the plywood playhouses - donated to the Bayleys Foundation to raise money for sick children's charity Make-a-Wish New Zealand - had bids up to $100 or more by last evening and have another week until the Trade Me auction hammer falls.

The second-highest bid was sitting on the Gingerbread House, assembled and painted by Block contestants Sarah and Minanne Kong - and tidied up later by the TV3 show's professional builders.

Pressed for time, Sarah was filmed using a hot-glue gun instead of screws to hang her playhouse's front door, having previously cut a door opening by mistake in the back wall, leaving the structure with two doors.

Gingerbread House.
Gingerbread House.

The front door came off in the hands of the judge but the show host Shelley Ferguson said all the playhouses would receive "a bit of work" later from an expert to make sure they were safe.

A questioner on the Trade Me auction for the Gingerbread House asks: "Has the front door been fixed and does it still have the 'wrong' door in the rear?"

Bayleys replied: "Hi, yes the front door has been screwed on."

The playhouse plans were dreamt up by pupils of Mt Albert Primary School, a neighbouring suburb from where the Block's contestants are doing up houses on the show.

The plans became the Gingerbread House, the Castle, the Rocket and a playhouse with an indoor swing and named the "Colourful House" by the judge, a child, who declared it the winner.