Anwar Ibrahim, who heads an increasingly popular alliance, says the charges are meant to check his rise to power.
The prime minister, his ruling coalition under pressure, vows to end policies that favor ethnic Malays and to boost foreign investment.
Amid allegations of corruption and a drop in popularity, the party that has been in power for five decades tries to shore up support.
Anwar Ibrahim retook his parliament seat Tuesday. His goal: topple the government.
Observers say civil courts often defer to Islamic courts on key issues.