Figure 4 Prices of New Zealand’s export commodities (denominated in US dollars)  Source: ANZ.
Yes, export prices look likely to fall, and indeed have already done so in a number of cases, but in US dollar terms they have, on average, been at relatively high levels for much of the last year or so (figure 4), and in New Zealand dollar terms they have been pushed up even further by the low level of the kiwi dollar (figures 5 and 6).