The laying of concrete foundations for Christchurch's "cardboard cathedral" started this morning.

Concrete trucks have been on the Latimer Square site pouring since 4am, and are expected to be there for seven hours.

The first truckload of 180 cardboard tubes for Christchurch’s transitional cathedral was delivered to the city last week.

Each tube is 6m long and weighs 120kg. Altogether, 320 tubes will be used in the $5.3m cathedral, which is the brainchild of Japanese architect Shigeru Ban.

Completion of the A-frame cathedral – originally tipped for December – has been delayed by rain and now looks unlikely before February.

More than 17 suppliers and contractors have given almost $1m worth of time, labour and materials to its construction.

The generosity of these businesses has made a huge difference to getting the project off the ground, says the Rev Craig Dixon, spokesman for the cathedral.

“Insurance from ChristChurch Cathedral covers $4m of the build; however we still require a further $1.3million in fundraising, despite the donations from suppliers and contractors.”

Naylor Love project manager Stephen Lynch says the cardboard design ss his "most challenging operation" in 25 years in the construction industry.

"It's an amazing concept and it's amazing engineering to get that concept to work," he told the NZ Herald.

Meanwhile, contractor Naylor Love and cathedral staff have organised a working bee to paint the cardboard tubes this Monday (24 September).

The tubes need three layers of polyurethane for additional waterproofing, even though they will be covered by a polycarbonate roof.

Those wanting to join the working bee can contact Nikki Lee at the cathedral, 03-353-7883 or email volunteers@christchurchcathedral.co.nz

Over the next four weeks, laminate beams from the North Island to be inserted in the tubes. Construction of the cathedral will then begin off-site and the frame erected before Christmas.

Next Monday Naylor Love will begin pouring the concrete foundations.