Dominic Raab made the comments during a NATO Parliamentary Assembly in London (Picture: PA).
The Foreign Secretary has called on Turkey to show "maximum restraint" as its air and ground offensive in Syria enters its fourth day.
Dominic Raab warned the incursion weakens the fight against so-called Islamic State (IS) and risks worsening the region's humanitarian crisis.
The United Nations says 100,000 people in north-east Syria have fled their homes.
Meanwhile, reports say at least 11 civilians have died and dozens of fighters from both sides have been killed.
Speaking at the 65th NATO Parliamentary Assembly in Westminster, Mr Raab said: "Our position is crystal clear. This incursion is wrong.
"We want to see maximum restraint, and avoid taking our eye off the ball with Daesh (IS)."
Turkey views Kurdish forces in the region as terrorists.
The Kurdish-led Syrian Democratic Forces (SDF) played a leading role alongside US troops in defeating IS in Syria earlier this year.
But the controversial withdrawal of US troops from the area prompted the Turkish offensive.
A Turkish representative at the NATO assembly reiterated that the operation is "not an invasion" but a "counter-terror operation".
However, Mr Raab disagreed and said it is "weakening the overarching counter-terrorism goal of countering Daesh".
He also said the UK is "very concerned we're taking our eye off the ball".
The UK also played an important role in defeating IS in Syria, with RAF fighter jets based in Cyprus flying nearly daily missions over the country.
There are concerns that the fighting in the north-east could lead to the escape of IS prisoners and a resurgence in the extremist group.
Mr Raab's comments for "maximum restraint" echo those made by the NATO Secretary General earlier this week.
During a visit to Istanbul, Jens Stoltenberg also urged Turkey to "act with restraint" and to "avoid any unilateral actions that may further destabilise the region and escalate tensions".