By Clare Arthurs BBC Hanoi correspondent

About 40 million people across Vietnam are preparing to vote on Sunday in five-yearly elections for the Communist country's single-chamber National Assembly.

Three Communist Party officials have been disqualified from the final list of more than 700 candidates, one of them linked to a major underworld figure who is in jail on murder charges.

Ho's anniversary lends a patriotic flavour to election day

The Communist Party still oversees the selection of candidates and this year it has allowed 16 independents onto the final list.

Polling booths open at seven in the morning local time (0100 GMT) on an auspicious day, as Sunday is also the birthday of modern Vietnam's founder, the late Ho Chi Minh.

In preparations typical of what is happening across the country, Hanoi's voters have been regaled morning and evening with pavement loudspeakers urging them to fulfil their patriotic duty and choose good candidates for the National Assembly.

Over the past few days, bright red banners have been slung through the summer greenery of the city's tree-lined streets.

They remind people that the birthday of their much-loved Uncle Ho is also polling day.

Other signs implore voters to choose wisely and, in typical nationalist sentiment, to celebrate the long life of the Socialist Republic.

Better class of candidates

Perhaps one of the most politically significant messages of this five-yearly election is the reminder that the election of good deputies will help construct a Vietnam which is founded on good law.

One of the biggest issues in this campaign has been corruption.

Voters are choosing candidates who for the first time will have to declare their assets.

Also for the first time, there will be a minimum of one quarter full-time Assembly members and more than ever will have tertiary qualifications.

Vietnam sets quotas for the 500-seat chamber to ensure there is a mix of professionals, artists, ethnic minorities, religious leaders and women.

The military also gets solid representation although no quotas are announced.

Political signals

The changes to improve the quality of candidates are a recognition that Vietnam's engagement with the global community requires continuing improvements to its legal and corrupt judicial systems.

Observers are speculating about... a new prime ministerial hopeful taking a seat in Hanoi in the near future

The expulsion of three senior Party members from the list for not being of good character is an attack on corruption.

So too is the arrest this week of several Ho Chi Minh City police officers and a state prosecutor.

A string of senior police officers have now been linked to the same underworld figure, Nam Cam, as one of the disqualified candidates, Tran Mai Hanh.

Observers are speculating about whether that and the arrests signal a power shift in the south which could lead to a new prime ministerial hopeful taking a seat in Hanoi in the near future.