Thousands of people gathered in a park in downtown Singapore on the Labor Day public holiday to protest against some of the government's policies and voice their concerns over issues such as population and immigration policies and rising living costs.

In particular, many said they are worried that the ruling People's Action Party are allowing too many immigrants into Singapore, after a population white paper projecting a population of 6.5 million to 6.9 million for Singapore by 2030 released earlier this year raised eyebrows.

It was the second protest that saw thousands of local residents gathering since the white paper was released, though government ministers and senior officials have been making strenuous efforts to explain how the projection was made and what it means.

The crowd began to gather in the afternoon for the protest. Organizers lined up more than ten speakers, including social workers as well as opposition party members.

Tan Jee Say, a former senior civil servant who contested the presidential election in 2011 but failed, also gave a speech at the protest.

Some of the speakers voiced their concerns over the impact of the inflow of immigrants on the Singapore society, with one saying that he does not want to see Singapore become a society of immigrants even though the city state has been an immigrant society in the early years.

Another speaker said that the real income of the workers at the bottom have not increased much over the recent years, and that the large amount of foreign labor pushed down the wages of local low- income workers.

Organizers said an estimated 5,000 people showed up for the protest on Wednesday afternoon.

Public gathering of huge crowds has been rare in Singapore over the past decades.

The White Paper on Population, released earlier this year, projected that the population may grow to between 6.5 million and 6.9 million by 2030, from the current 5.38 million. It says that the government may need to raise the total fertility rate and have 15,000 to 25,000 immigrants per year.

The number 6.9 million made headlines. Many voiced their concerns for continuing to grow the population as it is already getting crowded on the commuter trains and buses.

The government has strenuously emphasized that the number is a planning parameter, not a target. Officials also said that the government needs to improve the way it communicates with the people.

Prime Minister Lee Hsien Loong had said, "6.9 million is not a target, this number is used to help us plan for future infrastructure. We will use number as reference."

Lee said the Singapore government is not pursuing economic growth blindly but the objective is to ensure that the next two generations can continue to live happily in society.

Beyond 2020, things are still vague and uncertain, he said. " Nearer to 2020 we will review policy, population projections. Then we can decide how much further we should slow down ... reduce workforce growth rate to 1 percent or cut even further?"

"Do we see the population growing indefinitely? No." he said, adding that the resident population is going to stabilize and the non-resident population will also eventually level off.