Kiwis give their time and effort to charities, but not their cash.

Include a Charity week kicks off today and New Zealanders are being encouraged to leave more money in their wills to charities.

James Austin, the CEO of the Fundraising Institution of New Zealand, said bequest fundraising can make a sizable difference to the way charities run in New Zealand.

Yet the philanthropic act is not common in New Zealand.

"New Zealanders give their time, give their expertise, give their enthusiasm, but we are not very good, necessarily, at giving cash because we haven't been asked to in the past."

He argued some of the problem stems from the fact many Kiwis just don't make wills.