HONG KONG, Aug 11 (Reuters) - Poly Network, a decentralised finance platform, said it was hacked on Tuesday, losing an estimated $600 million according to reports of funds held in complicit wallets. The hack appears to be one of the biggest in decentralised finance, or DeFi here, peer-to-peer cryptocurrency platforms that allow transactions without traditional gatekeepers such as banks or exchanges. Poly Network allows users to swap tokens across different blockchains. The stolen funds amount to more than the criminal losses registered by the entire DeFi sector from January to July of a record $474 million, according to a report from crypto intelligence company CipherTrace published on Tuesday. Poly announced the hack on Twitter here, where it also posted details of wallets where it said the money was transferred, urging people to blacklist tokens from those addresses. Poly tweeted that it planned to take legal action and urged the hackers to return the assets. It did not immediately respond to a request on Wednesday for more detail about the incident. The value of the tokens in the wallets cited by Poly was just over $600 million at the time of the announcement, according to crypto trade publication The Block. The chief technology officer of Tether, a stablecoin, said on Twitter the company had frozen $33 million connected with the hack, and top management at large crypto exchanges responded to Poly Network on Twitter saying that they would try to help. Reporting by Alun John in Hong Kong and Tom Westbrook in Singapore; editing by Jane Wardell Our Standards: The Thomson Reuters Trust Principles.