Hi Len,

When shipping a 20kg package to Australia via China Post by sea, you generally have some flexibility in packaging, but there are important considerations:

1. Cardboard Box vs. Plastic Checkered Bag (编织袋)
Cardboard Box:

Recommended by China Post for international shipping, especially for heavier items.

Provides better protection and is less likely to tear during transit.

Must be sturdy and securely sealed with packing tape.

Plastic Checkered Bag (Jumbo Woven Bag):

May be allowed, but depends on China Post's current policies (some branches are strict).

Must be strong, tear-resistant, and properly sealed (stitched or taped shut).

Risk: If the bag is deemed unsuitable, China Post may refuse shipment or require repackaging.

Not ideal for fragile or high-value items (less protection than a box).

2. China Post’s General Packaging Rules for Sea Freight
Must be durable to withstand long transit times (sea freight takes weeks/months).

Should be properly sealed to prevent damage or tampering.

Maximum weight limit per package is usually 20-30kg (confirm with your local post office).

Address must be clearly written or attached on a label (plastic bags should have a secure label).

3. Recommendations
For a 20kg shipment, a double-walled cardboard box is the safest choice.

If using a plastic woven bag, reinforce seams with strong tape and ensure the address label is waterproof.

Check with your local China Post branch before packing, as rules can vary.