The monthly Singapore Sweep lottery is being revamped with a bigger jackpot and more chances to win, starting from May's draw.

The first prize jackpot will rise to $2.3 million, up from the current $2.2 million. And a new 2D prize will be introduced, with a record high one in 11 chance of winning.

To get the new 2D prize, punters must match the last two digits of their seven-digit ticket number to any of nine winning numbers. There will be 315,000 such prizes of $6 each.

The existing 3D prize, which requires the last three digits to match, will be removed. Also being removed are the Super Sweep prize of at least $300,000 - in which all seven digits and a letter must be matched - and the 100 cascade prizes of $10,000 each, which require five matching digits.