He said it was a significant step for New Zealand to be invited to participate in the group and demonstrated the growth of New Zealand's reputation in international trade.
The meeting will focus on trade liberalisation.
Mr Groser said ministers would discuss how economies were increasingly interconnected through global value chains and what it meant for trade and economic policy.
"They will also focus on trade as a source of growth and jobs, and explore ways to keep markets open to achieve further trade liberalisation," he said.
Mr Groser will travel to Mexico from Indonesia, where he has been with Prime Minister John Key.
The members of the G20 are: Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Republic of Korea, Russia, Saudi Arabia, South Africa, Turkey, United Kingdom, United States, the European Union.