Remember Malcolm Turnbull's taxpayer-funded $300,000 lunch in China? Turns out it really cost more than $500,000.

The Prime Minister rubbed shoulders with some of China's richest and more powerful people at the gala lunch – the grand finale of a week-long Australian trade and investment showcase – in Shanghai last month.

Prime Minister Malcolm Turnbull and Lucy Turnbull at the Australia Week in China gala lunch in Shanghai on April 14. Credit:Andrew Meares

China is Australia's largest trading partner, with two-way trade valued at $150 billion last year.

Government tender documents at the time revealed the lunch would cost taxpayers at least $284,962 in catering, plus venue hire. But another contract notice – released weeks later – shows Austrade also paid Hong Ling Dai Event Management $233,641 to organise and run the lunch.