NATO Patriot missiles deployed in Turkey to protect against a spillover of the conflict in neighbouring Syria will be operational this weekend, a senior NATO officer said Wednesday.

"We expect to have an initial operating capability this weekend, that's what we're aiming at. This is when we will have the capability to defend some aspects of the population," said British Brigadier General Gary Deakin.

The first two Patriot missile batteries to operate have been supplied by The Netherlands and will deploy in the southern city of Adana, arriving on station at the weekend to plug in to the NATO command and communication network, he said.

Two German Patriot missile batteries will be positioned in the southeastern province of Kahramanmaras while a further two US batteries will stationed in Gaziantep, just 50 kilometres (30 miles) north of the border.

Each contributing nation has also sent up to 350 troops.

"The full capability, we expect to deliver at the end of the month," the NATO officer said.

"We estimates that once it is in place at those locations, we will provide protection against missiles for up to 3.5 million Turkish people," he added.

Turkey requested help from its NATO allies after shells landed on its border areas from Syria in October, killing several villagers.

NATO approved deployment of the US-made missiles, effective against aircraft and short-range missiles, in December, saying the use of ballistic missiles by the Syrian regime posed a threat to Turkey.

But Syria's allies Iran and Russia oppose the deployment, fearing that it could spark regional conflict also drawing in NATO.

NATO insists the measure is purely defensive.