In your translation, the first thing I would worry about is making sensical variable names, particularly for those arrays. Regardless, much of that translates directly.

Nwt and Ndt are 2D arrays, Nt is a one dimensional array. It looks like you're looping over all the 'columns' in the z array, and generating a random number for each one. Then you increment whichever column was picked in Nwt (row w[i]), Ndt (row d[i]) and Nt. The actual random value is stashed in z.

#Literal translation
for i in range(N):
    t = Random.randint(0,T) #Not sure on this... but it seems likely.
    z[i] = t
    Nwt[w[i]][t] += 1
    Ndt[d[i]][t] += 1
    Nt[t] += 1

#In place of w= ivec(N);
w = [0]*N
d = [0]*N
z = [0]*N

#In place of Nwt = dmat(W,T)
Nwt = [[0.0] * T] * W
Ndt = [[0.0] * T] * D

EDIT: corrected w/d/z initialization from "n" to "N"

Note that there are still some things wrong here, since it looks like N must equal W, and D... so tread carefully.