Singapore has topped the rankings as the best place for expatriates to live and work for the fourth year in a row.

It secured the top spot by doing well in the three main categories - coming third for economics, fifth for families and sixth for experience.

The annual HSBC survey polled 22,318 expats around the world, including about 500 here, in March and April. It found that 45 per cent of those in Singapore said they initially moved here to progress their careers, higher than the global average of 35 per cent, while 38 per cent did so to improve their earnings. The global average was 24 per cent.

It was not all the lure of money though - around 25 per cent said they moved here simply because they wanted a challenge.

As far as pay goes, the highest expat salaries were in Switzerland, the United States and Hong Kong.

Expats here earned an average of US$162,200 (S$224,000), about US$56,000 more than the global average, placing Singapore in fifth place.

But half said they could not afford a property here, with most opting to buy in their home nation.

Switzerland was again top, with average pay of US$202,900, twice the global average, but only eighth as a place to live and work in due to the high cost of raising children and difficulty in making friends.

When it comes to their personal lives, 45 per cent of expats polled here said they found a long-term partner in Singapore. And 60 per cent of parents here found their children's health and well-being to be better than at home. The global average was 45 per cent.

Mr Anurag Mathur, head of retail banking and wealth management at HSBC Bank (Singapore), said it was "no surprise that Singapore remains an expat drawcard", given well-established financial markets and strong economic growth. "But the real kicker is the lifestyle. While 19 per cent were initially sent by their employer, almost half (47 per cent) chose to stay," he added.

Sweden was top for family; while New Zealand, Spain and Taiwan scored highest in the experience category.