AS A schoolboy, Deputy Prime Minister Tharman Shanmugaratnam juggled studies with representing his school in athletics, football and cricket, as well as playing hockey for the combined schools team.

These days, Singapore's Finance Minister and the man in charge of the annual Budget has a tough balancing act of another sort.

The widening - and worrying - income gap has made it necessary to focus more on social equity, and this year's Budget continues a theme from previous editions, with measures such as an expansion of the Workfare Income Supplement.

Singapore's Gini coefficient is among the highest in the developed world. The measure of income inequality, between zero and one, rose from 0.43 in 2000 to 0.452 in 2011, and to 0.459 last year, despite government transfers. Those on the lower rungs of society are also finding life harder in the face of rising living costs. While all other household incomes grew last year, those in the bottom 10 per cent saw theirs shrink by 1.2 per cent.

And as Mr Tharman presses on with efforts to redistribute the fruits of economic growth, he will have to juggle tensions on several fronts - the rich, the low-income group, and the Government's own fiscal position.

First, the upper classes. Already paying a sizeable portion of total tax revenue, they will have to cough up more from now on, and possibly even more in future.

The Budget included revisions to how luxury property and high-end cars are taxed, to make the tax structure more progressive.

Some have dubbed these "Robin Hood taxes", since they take from the rich to give to the poor.

Studies have shown that the top 11 per cent of earners already contribute almost 80 per cent of total tax takings, compared with 45.1 per cent for the United States and 31.6 per cent for Organisation for Economic Cooperation and Development (OECD) countries. That means Singapore is already more tax-progressive than the US and OECD average.

Might personal income tax rates be the next frontier?

In countries such as the US, Britain and France, there has been much debate over whether income taxes for the super rich should go up.

Prominent investor Warren Buffet said in 2011 that the richest Americans enjoy an unfairly generous tax regime. Taxes were a major debate topic during last year's US presidential election, and President Barack Obama has since increased taxes for the wealthy.

Closer to Singapore, China and India both raised taxes for the rich last month, to narrow the gap between the urban elite and rural poor.

But there may not be much scope to raise income taxes here without affecting Singapore's international competitiveness. At 20 per cent, Singapore's top marginal income tax rate is one of the friendliest in the world, but is above close competitor Hong Kong's top marginal rate of 17 per cent.

Another solution may lie in expanding the progressive tax structure beyond cars and homes. Artwork, yachts, eating at fine dining establishments and other playthings of the rich could also incur wealth taxes.

Estate duty - a remnant of the British colonial system, and laid to rest in 2008 - could be revived so that those who die and leave behind assets above a certain thres-hold are levied a "death tax".

But can the Government get buy-in from a broad swathe of the upper class? Already, some are grumbling that they may as well migrate if taxes continue to rise for them.

A new social compact has to be forged, such that the better-off Singaporean living in Bukit Timah does not mind paying higher taxes so that the flat dweller in Bukit Batok can share in the fruits of growth.

Another challenge looms on the horizon in how the Government deals with the lower-income group.

Even as it strengthens social safety nets, the state has to ensure that the motivation to work hard, which contributed to Singapore's remarkable growth story and place in today's global landscape, is not whittled away.

The experience in Europe shows how an entitlement mentality can build up under a welfare system. Immigrants in Nordic states prefer to rely on state handouts permanently than hunt for a job, leading to discontent among citizens.

Avoiding unemployment payouts, and ensuring that most benefits are tied to work, as is the case for the Wage Credit Scheme, is one way to preserve the drive to work.

Announced during the Budget, the scheme involves the state co-funding 40 per cent of employees' wage increases for three years. It applies to workers with a gross monthly salary of $4,000 and below.

Going forward, could some state handouts be linked to the number of years an able-bodied citizen has spent in the workforce? This could be extended to low-income retirees, possibly a significant group, given that the numbers of those above 65 in Singapore will triple by 2030.

It will show the Government's continued emphasis on self-reliance, even as it seeks to ensure the elderly are well taken care of in their silver years.

This proposal would mean that stay-at-home mothers and housewives will be left out, but they could still benefit from blanket voucher schemes such as the GST Voucher.

Lastly, even as the state tries to achieve greater social equity through tiered subsidies for services such as childcare and health care, it must be wary of tilting too much in the direction of universal welfare.

Already, some are asking if the Wage Credit Scheme, which will last for three years, is the first step to a permanent wage subsidy grant to companies for low-wage and middle-wage workers.

The danger is that once such subsidies are entrenched, it becomes almost impossible politically to end them.

And the demographic challenges of a rapidly ageing society and slowing social mobility mean that more will inevitably have to be done to keep the widening income gap in check.

That means balancing the Bud-get will get tougher, and be a different ball game in future.

But if Singapore is to stay ahead, the juggling has to continue.