Pakistan's anti-corruption body has arrested former president Asif Ali Zardari, widower of assassinated ex-premier Benazir Bhutto, in a multi-million dollar money laundering case.

Monday's development came hours after a court in Islamabad rejected a request by Zardari and his sister Faryal Talpur for an extension of their bail that would have allow them to remain free pending trial in the case.

The court's decision paved the way for the National Accountability Bureau to arrest the two.

However, the anti-corruption body did not arrest Zardari's sister and no explanation was given.

Zardari, currently a politician in the lower house of Parliament, and his sister, also a politician, have been accused of having dozens of bogus bank accounts.

Earlier on Monday, the two attended the court hearing amid tight security.