The worlds recycling trade association has officially asked China to postpone the day it will start turning away unregistered imports to October 1.
The influential Asian country has said that all incoming shipments of recovered waste must have a certification number from July 1.
But many firms are unlikely to have completed the complicated, uncertain and not fully translated registration procedure in time.
So the Bureau of International Recycling (BIR) has urged China which is set to consume 60% of the worlds metal by 2010 to put its deadline back three months.
The trade association has sent a letter to the General Administration of Quality Supervision Inspection and Quarantine of China (AQSIQ) expressing its concerns.
A spokesman said: BIR points out that very few companies would be able to meet the registration deadline as the latest announcement, which was giving details of the application procedure, had only been released on May 8.
BIR urges AQSIQ to move the registration deadline from July 1 to October 1.
BIR members send around 60% of the metal scrap and recovered paper China imports each year, as well as huge volumes of recyclable plastic.
The spokesman added: BIR will prepare a list of questions for which BIR members urgently need accurate answers. If too many issues remain unresolved, BIR will try to arrange a high-level meeting with the Chinese authorities in Beijing.