Can't shift on cold start

Hi,

I own this P11 Primera for 6 months now, love most of it but recently I find that I have problem shiftting the automatic shifter in the morning when cold. The shifter becomes very hard and near impossible to shift.

Only when the rev falls to 1000rpm or below then shifting becomes easy.
By then I would waited for about 2-3mins.

Is there a problem with the automatic transmission ?