Yellow umbrellas and makeshift tents were back in central Hong Kong Monday as protesters gathered a year to the day since huge pro-democracy rallies brought parts of the city to a standstill.

But with crowds numbering just a few hundred, the turnout was a reflection of the movement's loss of momentum after failing to push Beijing into allowing fully free leadership elections.

At the height of the 2014 protests, which lasted for more than two months, tens of thousands regularly gathered to demand political reform.

Yet despite the unprecedented rallies which garnered extensive coverage across the world, protesters were unable to force change.

Frustrated activists now say they need to regroup and come up with new strategies, conceding that changing the minds of Beijing and the Hong Kong government is currently a hopeless task.

Around 500 protesters gathered at the former main rally site in the financial district of Admiralty on Monday afternoon, jeering police who warned them not to block roads.

Rows of yellow umbrellas -- symbol of the pro-democracy movement -- several tents and a huge banner reading "I Want Universal Suffrage", lined the pavements.

The major highway through Admiralty was the focal point for the pro-democracy camp during the protests, when thousands of tents sprawled across the road.

Protest leaders on Monday encouraged the crowd to fight on.

"The authorities will still be against us, but that doesn't mean we will give up," said student leader Lester Shum.

Occupy Central co-founder Benny Tai called 2014 "one of the most important years in Hong Kong history".

"The Umbrella Movement... was just the beginning for Hongkongers in their quest for democracy," he said.

Some protesters expressed their anger at the lack of progress.

"We have not achieved universal suffrage," a woman in her 30s, who gave her name as Lam, told AFP.

"Society is not geared to helping Hongkongers."

Lam had brought her young son to the gathering.

"He knows that what we are doing is to avoid a fake election," she said.

Others relaxed in the sun and browsed stalls of Umbrella Movement memorabilia.

One couple posed for pre-wedding photos, the bride-to-be in a strapless white wedding dress with a construction helmet -- often worn by protesters during the rallies.

Dozens of pro-Beijing supporters also marched in central Hong Kong on Monday afternoon, shouting "Hong Kong people have had enough!". They accuse democracy activists of disrupting daily life in the city.

- Activists detained -

Occupy Central was launched exactly a year ago, calling for fully free leadership elections in the semi-autonomous city, following more than a week of student protests.

Thousands joined the already large crowds after police fired tear gas in the afternoon of September 28 last year, a move that shocked the public and galvanised the Umbrella Movement -- named after the umbrellas protesters carried to shelter from sun, rain, tear gas and pepper spray.

The protests began after China's central government said it would allow a popular vote for Hong Kong's leader in 2017, but insisted candidates were vetted.

The electoral package was voted down in June by pro-democracy lawmakers unhappy with the restrictions, leaving the territory with its existing system where the leader is chosen by a pro-Beijing election committee.

Hong Kong has been governed under a "one country, two systems" arrangement since it was handed back to China by Britain in 1997.

It allows far greater civil liberties than on the Chinese mainland, but there are growing fears those freedoms are being eroded.

Amnesty International called Monday for Beijing to release eight mainland activists detained for supporting last year's protests.

Their support included posting messages and pictures online and holding banners in public with messages, Amnesty said.

It comes after Human Rights Watch last week called for an "independent and thorough investigation" into the Hong Kong government's handling of the Umbrella Movement.

A number of the city's activists are facing court cases over the protests while police officers allegedly involved in beating a protester have yet to be prosecuted.