The 24-year-old winger, who has 22 caps, scored 20 goals in 68 games for the Dutch first division side last season. He will now undergo a medical before the transfer is completed.
Brendan Rodgers, the new Liverpool manager, has already signed Swansea City midfielder Joe Allen and Italy striker Fabio Borini from AS Roma for the new campaign.
Liverpool travel to West Bromwich Albion for their first game on Saturday.
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