There's been a message of celebration and frustration, at the first of hundreds of protests against Donald Trump's cutbacks to science funding.

Christchurch has hosted the first of 500 science marches being held around the world today.

Prominent scientists and Federated Farmers members are also attending protests in Dunedin, Queenstown, Wellington, Palmerston North and Auckland.

Canterbury University associate professor Bronwyn Hayward says speakers at the Christchurch event had a mixed message.

She says it wasn't a traditional slogan protest and the mood was mostly celebratory, but some people wanted New Zealand to increase action on climate change.

The largest protests are expected to take place in the United States overnight.