A chaotic sit-in to protest against a trade deal with China has shut down Taiwan's parliament and exposed deep divisions over the island's identity after seven decades of living apart from its vast, undemocratic rival across the strait.

The mainly student protesters — who proffer sunflowers as a symbol of hope — denounce the pact as an arrangement suiting Taiwan's wealthy. They say it will lead to mass encroachment by China, and its one-party mindset, on the island's cherished democratic values and institutions.

Its advocates, including Taiwan's president and his government, say it is a vital step to normalizing relations with Beijing and will provide jobs and improve living standards.