The Emergency Management Minister says smoke is dissipating from the fire still raging on Christchurch's Port Hills.

The blaze has burned through at least 650 hectares since it broke out yesterday, triggering evacuations.

The fire is yet to be contained, but people are being allowed back into homes on Hoon Hay Valley and Early Valley Roads.

Others will have to stay another night away.

Minister Mark Mitchell says firefighters are working incredibly hard.

"Today, they had an additional two fixed-wings in there, putting fire retardant in ridge lines and things like that. Their response was so quick."

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