Addressing a special session of the World Trade Organization, Bachelet warned against the rising threat of "protectionist trade policies in some countries", without mentioning Trump directly.
"We are at an inflection point", she told the WTO in Geneva. "Regional integration is crucial ... This is not an option. It is an absolute necessity".
She recalled two days of high-level meetings hosted by Chile earlier this month involving 11 countries that had been part of the defunct TPP, which were aimed at reviving some of the gains made during TPP negotiations.
Negotiated under former US president Barack Obama, who wanted to counter China's rising influence, TPP would have slashed tariffs and tightened trade ties between countries accounting for some 40 per cent of the world economy.
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Trump's decision to pull the United States out of the TPP marked his administration's first major strike on the global trading system he repeatedly blasted during his presidential campaign.
His government has since threatened to ignore WTO decisions, which help define the rules of international trade.
Bachelet, during an earlier speech at the UN rights council, took a veiled swipe at Trump's controversial bid to build a wall along the US border with Mexico.
She said that "no country, regardless of how powerful it is", can insulate itself from the problems facing an increasingly interconnected world.
They "cannot be resolved by building walls," she said.