Taiwan can't afford to hike its defence budget to more than three percent of GDP, the new leader of the democratic island's biggest opposition party told AFP, which could derail the government's spending plans.Taiwan president Lai Ching-te, who leads the Democratic Progressive Party (DPP), aims to boost defence spending to more than three percent of GDP next year and five percent by 2030, following US pressure to spend more on protecting itself against a potential Chinese attack.