Mr Nazarbayev has been president for 17 years

The vote was triggered by changes to the constitution that the government claims will make parliament stronger.

Seven parties are standing, but analysts predict the governing party of President Nursultan Nazarbayev will, once again, win a huge majority.

International monitors have judged previous polls to be deeply flawed, and Kazakhstan is under pressure to hold these elections in a more open manner.

The European security organisation OSCE has set up an election observation mission in the country, to monitor the electoral process.

Early criticism

Nur-Otan, the country's ruling party, marked the beginning of the month-long race with balloons and banners in one of Almaty's parks.

A few hundred party members listened as candidates praised President Nazarbayev, the head of the party.

On the other side of the city, opposition leaders laid flowers and chanted "Victory is ours!" as they marked the first day of campaigning.

"We are backed by truth and justice," Bolat Abilov, one of the leaders, told a group of supporters.

"We will get into parliament, form the government and press ahead with reforms Kazakhstan has always dreamt about," he is quoted as saying by Reuters news agency.

But analysts predict the opposition's chances of gaining a significant presence in parliament as a result of the 18 August polls are slim.

There was only one opposition seat under the previous assembly.

Some observers say that, under pressure from the international community, President Nazarbayev might allow a greater opposition presence this time.

But one opposition leader is already critical of the way the campaign is going.

"We tried to put our TV advertisements... showing what our party is standing for," he told the BBC.

"But all TV channels, all of them, denied us. But at the same time, each evening, you could see a lot of Nur-Otan TV advertisements."

Even the government admits that political reform is lagging behind economic changes.

Kazakhstan's economy, fuelled by billions of western investment, is growing faster than any other in the former Soviet Union.

Mr Nazarbayev is ambitious about gaining more political clout internationally.

His recently proposed constitutional changes - giving more power to parliament to prove that Kazakhstan is serious about democracy - triggered the early election.

But the problem, observers say, is that none of the changes are significant enough to have a real impact.

The BBC's Natalia Antelava in Almaty says that even the positive elements are being overshadowed by one single amendment to the constitution, which allows Mr Nazarbayev to run for office as many times as he likes.