A total of $4.4 million was committed for last month's Singapore Day celebrations in London, attended by more than 9,000 people.

Deputy Prime Minister Teo Chee Hean said the total expenditure is still being finalised, but "should be close to the budgeted amount".

He cited the details in a written parliamentary answer on Monday to Nominated MP Faizah Jamal. She had asked about the cost, the number of people flown from Singapore for the March 29 event at Victoria Park, and ensuring future events use eco-friendly, non-disposable wares.

The celebration has been held in a major city almost every year since 2007 to gather overseas Singaporeans and give them a taste of home, from hawker fare to home-grown entertainment.

An estimated $6 million was spent on the Singapore Day in London in 2009. The expenditure has varied in other cities, from $2 million in Shanghai (2011) to $4 million in New York (2012). A total of $3 million was budgeted for Singapore Day in Melbourne in 2008.

Mr Teo, who attended the event in London with Prime Minister Lee Hsien Loong, noted that Singapore Day is put together with the support of partners from the private, public and people sectors, many of whom volunteer their services.

Public service agency representatives try to tie in their participation in Singapore Day with other official duties.

The Education Ministry, Ministry of Health Holdings and Contact Singapore held recruitment sessions in and outside of London in the lead-up to the recent Singapore Day.

Among the 182 personnel from Singapore were representatives from public sector agencies, food crew, concert artistes and production crew.

As for environmental concerns, Mr Teo said Singapore Days are held in public parks, many of which have stringent environmental regulations.

"Whenever possible, portable items such as kitchen equipment used by the hawkers are recycled for subsequent Singapore Days," he added.