1<ion-datetime #dateTime style="display:none" displayFormat="h:mm A" pickerFormat="h mm A" [(ngModel)]="startTime"></ion-datetime>
2<button (click)="openStart()"></button>
3and then in your code
4...
5//first create a reference to the datetime control:
6@ViewChild('dateTime') sTime;
7...
8//then add your event code:
9openStart()
10{
11 this.sTime.open();
12}