To confirm my post from yesterday (I did further investigation today):

The most common steel sourced from China is steel plate (used in structural steel buildings). Followed by that it is the structural steel (beams/columns etc) itself, however this is less common as the standard sizes in Aus/nz are different to other countries.

Reinforcing steel is rarely from overseas. The New Zealand standard that seismic grade reinforcing has to made made in accordance with is much more rigorous than for structural steel. Hence NZ suppliers have a better hold on the market.

Quality of Chinese steel is a huge issue. In some cases steel has been provided with forged production information that says it meets certain standards when it doesn't. Sometimes it's hard to get any information at all. It is especially a problem from seismic grade steel because not only does it need to be at least a certain strength, but it cannot be stronger than certain upper limits. This means they need to pick up their game if they want to truly displace New Zealand suppliers.

When it comes to the split between the above in terms of steel volume I can't help.

Happy to answer any questions... Disc: I provide the above information as an engineer rather than an investor in STU. I am monitoring happenings to see if value presents itself however.