Cyprus on Thursday slammed as illegal a water pipeline connecting Turkey to the Turkish-held north of the divided island, saying it undermined ongoing peace talks.

Nicosia's foreign ministry said the construction of a 106-kilometre (65 mile) underwater pipeline taking water from a damn near the Turkish port of Mersin to breakaway northern Cyprus "violates international law".

Cyprus has been divided since 1974 when Turkish troops invaded and seized its northern third in response to a Greek-backed military coup seeking unity with Athens.

A new peace process got underway in May in an effort to end the island's decades-long division.

The current round of UN-brokered peace talks is widely seen as the best opportunity for a lasting peace deal but Cyprus' foreign ministry said the pipeline comes at a "particularly critical phase in the process".

It accused Ankara of seeking to "maximise Turkey's influence and control over Cyprus".

Cyprus is prone to drought and water shortages with the government-controlled south building desalination plants to bolster water reserves.