A warning not to count down the days left of lockdown, because there's no certain end yet.

New Zealand's approaching halfway of the four week lockdown - but the government's been clear from the outset it could go longer.

Clinical psychologist Jacqui Maguire says research shows quarantine lasting more than 10 days can impact mental health, so the government has to be careful how long it lasts.

She says people should remain realistically hopeful we're on our way out of lockdown.

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