Sequoia Capital Chain also participated in the round, which comes on top of a $3 million raise last year.
Targeted at businesses rather than consumers, the Airwallex platform can support thousands of transactions per second and claims to provide a more cost-effective alternative to existing payment networks.
It is powered by a sophisticated FX and payment engine and a transparent pricing model designed to avoid inflated margins and minimise market risk.
The firm, which joined the Mastercard Start Path accelerator programme last year, says that it will use the new funding to propel the release of its suite of APIs and fuel international expansion, notably into Europe.
Jack Zhang, CEO, Airwallex, says: "The continued growth of international trade and the global economy rely on efficient cross-border transactions.
"Our mission is to eradicate the burden of international payments so that businesses can transact across borders with ease. Armed with a growing number of financial services licences and partnerships across numerous jurisdictions, we aim to make international payments as cheap and simple as domestic payments.
Australian cross-border payments firm Airwallex has raised US$13 million in a Series A funding round led by Chinese Internet giant Tencent and joined by Mastercard