The brand appointed Lucky Generals to its retained UK account in July last year as it aimed to take market share away from rivals Apple and Samsung.
However, OnePlus said it has no plans for UK creative work this year.
The latest work from Lucky Generals promoted the features of the OnePlus 5T phone in a test centre where people dodge cacti being catapulted at them and a vicious dog.
OnePlus positions itself as a high-quality smartphone that seels at a much lower price that market leaders Apple and Samsung. It was founded five years ago by chief executive Pete Lau and has evolved its word-of-mouth advertising approach in recent years to include traditional advertising.
A spokeswoman for OnePlus said of the agency review: "We are focusing on European projects over this year and with no plans to work with an agency on specific UK creative projects."
UPDATE: OnePlus has confirmed that it will be running work in the UK. The spokeswoman said: "We will be running creative work in the UK – we’ve always been very hands on and had internal teams dedicated to developing creative campaigns at both a European and UK level. We’ll be using campaigns developed by both our European and UK team with an agency at European level."