"So members are extremely concerned about all of this.''
Tests that were carried out last year on the locomotives, following revelations that Chinese-manufactured vehicles in Australia contained the product, had given the locomotives the all clear, he said.
"So clearly that's not true, and unfortunately the same company that's testing them now is the same one that tested them last year, and so there may be a wider discussion around that,'' Mr Butson said, adding that it is not illegal to import asbestos into New Zealand, as it is in other countries.
However, the wider issue was around Government procurement "skewed towards'' seeking the cheapest option, he said.
"These Chinese locos cost us a railway workshop in Dunedin, they cost us hundreds of skilled jobs, and now they may end up costing some of our members their lives, potentially.
"If these locos had been made in Dunedin, or even in any other first world country, we wouldn't be putting up with this rubbish. It's pretty symptomatic of why most Kiwis are sceptical about anything that comes out of China.''
Earlier KiwiRail said the inclusion of asbestos in the trains was in breach of a contract specification which clearly stated the material should not be used.
"We are clearly very disappointed with this situation and working closely with the manufacturers to understand how this could possibly have occurred. They have taken full responsibility for this and have undertaken to do whatever is necessary to rectify the situation as quickly as possible for us,'' Mr Reidy said.