BILLIONAIRE Microsoft co-founder Bill Gates has urged Australian parents to vaccinate their children, saying they are "there to help people".

Speaking at the National Press Club in Canberra Mr Gates was asked about the recent trend of wealthy educated parents opting to not vaccinate.

"Vaccinate your children," Mr Gates urged.

"Vaccines are there to protect people and thank goodness they are used hundreds of millions of times and so the net benefit is quite strong."

Mr Gates said if more and more parents chose not to vaccinate their children it would lead to deaths, and referenced cases in Switzerland where this had occurred.

"We have to be very very careful about vaccine safety but the existing ones are quite well established," he said.

Mr Gates addressed the NPC on foreign aid and said it was important for Australia to keep its commitment to increase aid spending to 0.5 per cent of gross national income.

He said vaccines in developing countries had saved millions of lives.

Earlier in the day Mr Gates met separately with Julia Gillard, Kevin Rudd and Tony Abbott.

Ms Gillard hosted a breakfast reception for the computer giant at The Lodge from 8am.

Mr Rudd had Mr Gates visit him in his parliamentary office and Mr Abbott met with the Opposition Leader shortly before making his address.

The billionaire is understood to have spoken with all three about the importance of aid spending.

Mr Gates is the world's richest person on the Forbes rich list, worth an estimated $70 billion.

He will take part in a special Q&A program on the ABC tonight at the University of NSW.

It will air at 9.35pm.

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