The government will ensure that all citizens will have equal opportunities to rise to the top and will assist the needy in services such as education, housing and health care, Goh said at the launch of the National Volunteer Center.

"However a more pertinent question to ask is what those of you who have benefited from the general increase in prosperity in Singapore have put back in to society," he said.

"The successful have the greatest moral responsibility to give back some of what society has allowed them to earn," Goh added.

A recent national survey showed that only 9.3 percent of Singapore's population do volunteer work, compared to Japan where one in every four persons is involved in community work, or in the United States where the figure is 56 percent, he noted.

The growing income divide in Singapore was apparent in figures released in May, which showed that the bottom 10 percent of the population earned less than an average of S$1000 (US$578) a month while the top 10 percent saw average income rising from $15,053 dollars to $15,541 dollars.

An income of $1000 dollars a month for a family of four is regarded as the poverty line. Singapore has a population of 3.1 million, excluding some 700,000 foreigners.