The Pakistan People's Party has 'finalised' its prime ministerial nominee amid speculation it could be former Speaker Yousuf Raza Gilani.

Bilawal Bhutto, the 19-year-old son of slain PPP leader Benazir Bhutto [Images], meanwhile arrived in Pakistan from Britain to announce the candidate who will head the party-led coalition government, a party spokesman said. Bilawal, who is studying at Oxford University, has been named Bhutto's heir apparent.

Senior PPP leader Nabeel Gabol, a close aide of Zardari, said the party had 'approved and finalised' its candidate and the name would be announced shortly.

The identity of the nominee has been wrapped in secrecy but Gilani, who was parliamentary speaker during Bhutto's government from 1993-1996, is believed to have emerged as the current front-runner, pipping a very strong contender Makhdoom Amin Fahim, who insists he is still in the race.

"The name of the prime minister will be announced when the (new parliament session) is reconvened for the election of the prime minister," which is expected next week, PPP spokesman Farhatullah Babar said.

Sources said Zardari decided to call his son from Britain for announcing the candidate to avert any rift within the ruling party.