Netherlands scored 105 for the loss of 4 wickets in their allotted 20 overs.
PNG in reply lost 9 wickets for 106 on the last ball of the 20th over.
The Lewas advance to the Shield final against China tomorrow, who beat hosts Thailand by five runs in the other semi final.
Meanwhile Bangladesh meet Ireland in the final of the World Twenty 20 tomorrow and advance to the 2016 ICC Women's World T-20 in India next year.
Bangladesh beat Zimbabwe by 31 runs while Ireland thrashed Scotland by 9 wickets in the World T-20 qualifiers semi finals.