One of China's most powerful officials said he would listen to political demands from Hongkongers in a conciliatory start to a visit Tuesday that has stirred anger in a city resentful of Beijing's tightening grip.

The three-day trip by Zhang Dejiang, who chairs China's communist-controlled legislature, is the first by such a senior official in four years and comes as concerns grow in semi-autonomous Hong Kong that its long-cherished freedoms are under threat.

While Zhang is ostensibly visiting to speak at an economic conference on Wednesday, the trip is widely seen as a bid to take the temperature in an increasingly divided city with a fledgling independence movement.

It has infuriated opponents, critical of a massive security operation that involves thousands of police and barricades protesters into designated areas out of Zhang's sight.

Police shoved back protesters gathered near the residence of the city's leader Tuesday night where Zhang was due to have dinner.

Seven members of pro-democracy political party the League of Social Democrats were arrested earlier after putting up protest banners, with three still detained.

A leading pro-democracy activist was also wrestled to the ground by police outside Zhang's hotel.

Wednesday will see several protest groups rally near the harbourfront convention centre where Zhang is due to speak.

Zhang arrived just before noon at Hong Kong airport where he was met by city leader Leung Chun-ying and a brass band.

In a short speech on the tarmac Zhang pledged to listen to a variety of political views.

"(I will listen to) people from all walks of life about any suggestions and demands regarding the implementation of 'One Country, Two Systems'," said Zhang, referring to the semi-autonomous system under which Hong Kong has been governed since being handed back to China by Britain in 1997.

He also said he would listen to "any suggestions and requests regarding the nation and Hong Kong's development".

Zhang declared he had brought a "caring heart" as well as "hearty greetings and good wishes" from China's President Xi Jinping.

At a meeting with lawmakers later Tuesday, Zhang said Beijing was satisfied with the work of the Hong Kong government.

"I feel that the future is bright for Hong Kong," he added.

He will meet four veteran pro-democracy lawmakers Wednesday evening, a rare move observers say is designed to defuse frustrations over stalled political reform.

- 'We won't back down' -

Hong Kong has been semi-autonomous since it was handed back to China by Britain in 1997, with freedoms unseen on the mainland.

But since mass rallies in 2014 for fully free leadership elections failed to win concessions, young campaigners have become increasingly frustrated.

Demosisto, a new party launched by student leaders behind the pro-democracy protests, is campaigning for a referendum to decide the city's future. It demanded in a statement posted on Facebook that Beijing allow Hong Kong "greater self-determination".

The party added "the Hong Kong people are resolute in determining our fate, and... any tokenistic diplomacy to beat us into submission will not be accepted as legitimate".

Authorities have cordoned off the convention centre with water-filled plastic barricades and paving stones have been glued down to prevent protesters using them as missiles.

Police are even patrolling Lion Rock hill overlooking the city, where pro-democracy banners have regularly been unfurled.

But activists from the League of Social Democrats managed to hang a banner calling for universal suffrage on a nearby hillside Tuesday morning.

Another, demanding the "end of Communist Party dictatorship", was hung on a highway from the airport into the city.

After its members were arrested over the banners, a Facebook post on the party's website said it would not back down.

"We are against the interference of Hong Kong affairs by the Chinese Communist Party," the post said.

A small group of pro-democracy protesters including student leader Joshua Wong chanted and held up signs calling for universal suffrage and self-determination near Zhang's hotel.

High-profile activist Nathan Law tried to breach the barricade and was tackled to the ground by police.

A rival group of pro-China demonstrators waved national flags nearby.

Zhang's visit is expected to help Beijing gauge whether city leader Leung should stand for another term -- his current stint ends in March 2017.

Like all Hong Kong leaders, Leung was chosen by a 1,200-member committee stacked with Beijing loyalists.