About 20mm of rain fell on the Port Hills fireground this morning.

Incident Controller Steve Kennedy says overnight crews made great progress eliminating many of the hotspots and also the deep seated burning at one of the largest skid sites.

The specialist drone crew continued thermal imaging overnight and has identified further areas that crews will focus on today.

Steve Kennedy says the rain was welcome and will help fire suppression. However it also means conditions will be slippery so access tracks on the steep terrain will be checked before crews start working on some parts of the fireground.

Firefighters will again be working with the support of heavy machinery and two helicopters are available.

© Scoop Media