The review gives Lowe London a chance to win back the position on the Nestlé UK roster it lost in February 2005.
It will come as a blow to JWT, which currently handles all Nestlé's UK confectionery advertising, following a realignment of duties that saw a number of chocolate brands moved from Lowe to the WPP-owned shop.
Nestle Rowntree launched Heaven into the UK premium chocolate market in January 2007. The launch came just a year after the company scrapped its luxury Double Cream brand due to poor sales.
Heaven is made from Swiss chocolate and is available in block and gift-pack varieties in five flavours - milk truffle, dark truffle, hazelnut creme, milk orange truffle and cafe latte.
The brand is not currently handled by a UK agency. Its UK launch was backed by a commercial created for its Australian launch last year.
The ad, created by JWT Australia, featured a woman taking a novel approach to speed dating, finishing her evening with her beau in under 30 seconds in order to spend time at home with a bar of the chocolate.