By Paul Anderson BBC correspondent in Islamabad

Critics say generals will still wield more power than elected civilians

According to early results from the first stage of the vote, the party of the Prime Minister, Zafarullah Jamali, the PML-Q, won more than half the seats chosen by Pakistan's four provincial assemblies.

There'll be more voting for the remaining 12 of the Senate's 100 seats, later this week.

But the PML-Q looks set to win many of those too.

Gains for religious alliance

Barring any unexpected lurches in voting patterns in the next round, Mr Jamali's party looks set to secure a simple majority in the Senate.

His military-backed coalition in the lower house operates with a thin majority.

The prime minister is hoping for a more comfortable margin in the Senate to remove any obstacles to the legislative agenda his government will be setting.

He also needs to be able to elect the chairman - an important post because the incumbent deputises for the president in his absence.

That said, the alliance of parties from the religious right, the MMA, has built on the unexpectedly strong gains it made in National Assembly elections last year.

It may emerge as the second-placed party in the Senate.

Civilian transfer

The election to the Senate is the second and final stage of what President Pervez Musharraf says is Pakistan's return to civilian rule after the military coup three years ago.

The upper house has the right to initiate legislation, and can delay law-making in the lower house - similar to constitutional democracies around the world.

However, many opposition politicians say the whole process has been flawed by vote-rigging and vote-buying - charges the main party has denied.

Government opponents also say the process is flawed by the amendments forced through by General Musharraf, among them one which enshrines the role of the military in the political process.