Hong Kong restricted Ireland to Roisin Upton's first international goal in the 18th minute during the first half.
However, the floodgates opened in the second half with Anna O'Flanagan and Katie Mullan both scoring twice.
Nikki Evans, Chloe Watkins, Rebecca Barry, Gillian Pinder and Nicci Daly were also on target as the Irish set up a likely quarter-final with Singapore.
After their 12-0 win over Kazakhstan on Saturday and Tuesday's 2-1 victory over hosts Malaysia, Ireland's quarter-final will take place on Thursday.
The tournament is Ireland's first round of qualification for the 2018 World Cup and they want a top-two finish to qualify for World League 3, where they could play in either Belgium (21 June-2 July) or South Africa (8-23 July) depending on rankings.
Ireland are the second highest ranked team in the tournament as they sit 16th, with only Italy, 15th, ranked above them.
Pool A has Italy joined by Thailand, Wales and Singapore with rankings of 15, 31, 32 and 43 respectively.
Ireland's women hammered Hong Kong 10-0 to win Pool B at the World League 2 tournament in Kuala Lumpur.