Ed,
First, I am assuming you refer to chinese firebelly newts. Second, I am also assuming that you have checked your water quality (no ammonia, no nitrates, no nitrites, reasonable pH, low water hardness, and if possible, no/low phosphates).
How long the land-loving phase lasts is indeterminate; it is up to the newts in question. New newts will often stay on land until they become acclimated to their surroundings. There are ways to accelerate the acclimation process. One is to gradually remove more and more of the land area. Another is to spray them with clean, dechlorinated water so they get used to water.
However, I advise against using these techniques with injured or highly stressed newts. Remember to always think like the newt; you have to become one with the newt.