Red and green parrot finches-breeding????

i have a pair of parrot finches.about a month ago they built an nest in the avairy which took then about 2 weeks to complete.since then for the last 2 weeks they have never been near the nest.i was just wondering if this is usual i thought they would be sitting on eggs now,maybe it the wrong time for them to breed but i am in the sub tropics thank you