The numbers signing up for KiwiSaver surged by 78,000 in April taking the total enrolments to 600,000.

Finance Minister Michael Cullen and Revenue Minister Peter Dunne said in a statement that the surge was a huge response to the Government's enhancements to the scheme.

"Over 2600 new KiwiSavers were signed up every day in April making it the biggest month for KiwiSaver yet," the ministers said.

Initial projections were for 270,000 New Zealanders in KiwiSaver after the first full year.

On April 1, the Government introduced compulsory employer contributions and the Government tax credits to support them.

" With well over 100,000 KiwiSavers under the age of 25 and a large number of low to middle income workers coming into the scheme we know that many KiwiSavers are new savers.

"Without this scheme these people would be falling behind in saving for their future."