The first batch of cleaning firms will get licences to operate in May.

All cleaning companies need to be licensed by the National Environment Agency (NEA) before September 1 to stay in the business.

A key requirement of the licence is to use a "progressive wage model" to help workers earn higher pay through training.

National Environment Agency deputy chief executive Khoo Seow Poh said at a press conference on Friday that since April, around 70 cleaning companies have submitted applications for licences.

He said the key challenge that the firms have is meeting the requirement of sending at least half of their staff for training.

"We are working closely with the Singapore Workforce Development Agency to ensure that there are sufficient training courses and places for the workers," said Mr Khoo.

The press conference was held to give at update of the licensing scheme for cleaning firms, which was announced by Deputy Prime Minister Tharman Shanmugaratnam in January.

The scheme ensures that all 55,000 local cleaners will earn at least $1,000 each month from September, up from $850 now.