Banks are reporting a surge in interest from customers keen on drawing down their KiwiSaver accounts to help pay for their first home.

New rules which came into effect at the start of the month mean first-time buyers who have been enrolled in KiwiSavers for three years can now cash-up their entire KiwiSaver balance, minus the Government's $1000 "Kickstart" contribution to fund their first home.

Previously they could only access their own and their employers' contributions and not an annual tax credit worth up to $521.

ANZ Wealth managing director John Body said ANZ's contact centre received more inquiries about KiwiSaver first-home withdrawals in the first week of April than it did in the month of April last year.

Westpac spokeswoman Haley Ritchie said, anecdotally, it appeared the number of calls it had received in relation to first home withdrawals had increased significantly. "Overall calls about KiwiSaver are up by about 15 per cent on the same time last year, she said.

BNZ's head of wealth and private banking Donna Nicolof said it had also seen the number of inquiries from KiwiSaver customers looking to make withdrawals to finance their first homes increase significantly. That was both in the run-up to the April change and subsequently, she said.

During March "KiwiSaver" was the fifth most searched term on the BNZ website, again indicating the level of interest from New Zealanders in utilising KiwiSaver to help them into a home of their own.

ANZ said some customers were confused about the rules surrounding HomeStart contributions. First-home buyers can get up to $5000 towards the cost of their home, or $10,000 if they are building a new home. But they must have been contributing at least 3 per cent of their income to KiwiSaver for a minimum of three years.

The HomeStart contributions can go up to $10,000 for existing homes and $20,000 for new builds if couples are buying a home together and both partners qualify.

KiwiSaver is now a significant part of the first-home buying equation but there are conditions and people need to know how it works so they can take full advantage of the scheme," Body said.

"KiwiSaver offers some great opportunities to help people buy their first homes but you must be actively contributing to KiwiSaver to qualify for the HomeStart grant, which a lot of people aren't aware of."

Building and Housing Minister Nick Smith forecast in March that the rule changes and HomeStart grants would "open the door" for 90,000 young people to buy homes over the next five years.