US Secretary of State John Kerry speaks at Singapore Management University in Singapore on August 4, 2015. (AFP Photo)

Asia-Pacific countries negotiating a vast free-trade pact are "nearing completion" of a landmark agreement, US Secretary of State John Kerry said today, days after delegates failed to seal the deal in Hawaii.Kerry said the 12 countries including the US and Japan negotiating the Trans-Pacific Partnership (TPP) had made good progress on reaching an accord following talks that ended on Friday in Maui, but "as with any complex negotiation...there remains details to be hashed out"."My friends, this is a moment of exceptional opportunity for the Asia-Pacific. We are nearing completion of a historic Trans-Pacific Partnership agreement on trade," Kerry said in a lecture at the Singapore Management University.He was making a half-day visit to the city-state before attending the ASEAN Regional Forum in Kuala Lumpur.Kerry praised the trade deal -- which will cover nearly 40 percent of the world's economy -- as an agreement that would have benefits beyond pure economic growth.The pact would raise labour and environmental standards, protect intellectual property, deter corruption and also ensure free digital trade and fair competition between state-owned enterprises and private firms, he said."Because major economies are committing to TPP's high standards, its influence will be felt throughout the region. It will send a message to people within the TPP and outside of support for good governance, transparency and accountability," Kerry said.Observers have said the delay in securing the deal in Maui last week complicates President Barack Obama's plans to secure the accord this year, and there is a risk of it becoming dragged into the 2016 presidential election debate.The deal, eight years in the making and vaunted as part of Obama's "rebalance" towards Asia in the face of an increasingly assertive China, faces opposition from his fellow Democrats who see it as too far-reaching.The TPP countries -- Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, Vietnam and the US -- have faced criticism for carrying out their negotiations in what opponents have charged is intense secrecy.Its many critics say the proposals indicate a deal moving more toward protectionism than free trade; one more about corporate benefits than boosting economies and development.But backers say the modern global economy needs new rules of the road to protect intellectual property-dependent 21st century industries not covered in traditional free-trade forums like the World Trade Organization.