The two nations are also currently in negotiations over a free trade deal, which would be the first for China with a developed nation.
The free trade deal was discussed when Howard and Wen held talks later Wednesday in Shenzhen, the economic boomtown in southern Guangdong that is just across the border from Hong Kong and will be one of the main beneficiaries of the Australian gas contract.
Although the two sides are a long way off from signing a free trade deal after five rounds of negotiations, both leaders expressed optimism.
"We hope to accelerate these negotiations," Wen said.
Howard arrived in Shenzhen from Indonesia on Tuesday night, with Wednesday his only full day in China. He was due to leave on Thursday morning, without visiting Beijing or Shanghai.
His commitment to a deep engagement with China — he has visited China nine times during his 10 years as Australian leader — stands in contrast to reservations often expressed by the United States.