Hong Kong's leader Leung Chun-ying has said open elections would result in the city's many poor dominating politics, as he ruled out democratic reforms before crucial talks aimed at ending three weeks of protest rallies.

In an interview with foreign media, carried in the Wall Street Journal and International New York Times hours before talks were due to start between student leaders and officials, embattled chief executive Leung Chun-ying said free elections were impossible.

Leung, whose resignation protesters have demanded, said if leadership candidates were nominated by the public then the largest sector of society -- the city's poor -- would likely dominate the electoral process.

"If it's entirely a numbers game and numeric representation, then obviously you'd be talking to the half of the people in Hong Kong who earn less than US$1,800 a month," he said in the interview.

Some major intersections in the semi-autonomous southern Chinese city have been paralysed for more than three weeks by mass rallies demanding free elections, in one of the biggest challenges to Beijing's authority since the Tiananmen pro-democracy protests of 1989.

China has offered Hong Kongers the chance to vote for their next chief executive in 2017. But only those vetted by a committee expected to be loyal to Beijing will be allowed to stand -- a proposal activists have labelled a "fake democracy".

The protests are taking place against a backdrop of rising inequality and soaring housing costs which leave many young people with little prospect of renting, let alone buying, their own homes in a city with one of Asia's widest wealth gaps.

Though largely peaceful, the rallies saw increasing violence in the past week as police tried to clear some of the intersections.

The talks are scheduled to begin at 6pm (1000 GMT) and will be broadcast live on TV. Demonstrators say large screens will be erected at the protest camps.

But there are fears that neither side will find common ground, with both sides seemingly unwilling to compromise -- potentially setting up further clashes between protesters and police.

- Trepidation over talks -

"I'm seriously worried about tonight," pro-democracy lawmaker Claudia Mo told AFP.

"If this is just going to be a political show -- where political animals form a political circus -- people will think: 'Well, let's just take to the streets again'."

Analysts and democracy lawmakers said Leung's comments on the poor were likely to inflame tensions further.

"It reflects the distrust the authorities have of the people... and it also reflects how the current political system is biased for the rich and against the poor," said pro-democracy lawmaker Fernando Cheung.

"The situation might get worse" if the government continues to deny concessions to democracy protesters, Surya Deva, a law professor at City University of Hong Kong, told AFP.

"Why should poor Hong Kong people follow laws and believe in the rule of law when they have no hope for political or economic empowerment?"

Leung made a dramatic U-turn last week by announcing a return to talks with the Hong Kong Federation of Students, one of the groups leading the protests, after abruptly pulling out of discussions a week earlier.

"One round of dialogue may not solve all the problems but to be able to hold talks is a good start," he told reporters on Tuesday.

But in a veiled threat to protesters, Leung hinted that China's patience could run out.

"So far Beijing has left it to the Hong Kong government to deal with the situation, so I think we should try our very best - and this is myself, the government and the people of Hong Kong - should try our very best to stay that way," the New York Times quoted him as saying.

Increased competition with wealthy mainlanders and anger at the cosy relationship between the government and Hong Kong's financial elite have left the younger generation deeply uneasy about what awaits them in adulthood.

Almost 20 percent of Hong Kong residents, or 1.31 million people, are under an official poverty line introduced in September last year.

Tens of thousands of low-income families and immigrants are forced to live in tiny subdivided units, unable to afford sky-high rents.