The drying up of Iran's largest saltwater lake is an "environmental issue" but some people seek to politicise it, media on Monday quoted the vice president for environmental affairs as charging.

"The issue of Lake Orumiyeh is an environmental challenge," Mohammad Javad Mohammadi-Zadeh, who is also head of Iran's Environmental Protection Organisation, told reporters after a cabinet session on Sunday.

"(But) some want to exploit the situation, politicise it and mount a social campaign," Mohammadi-Zadeh said.

Lake Orumiyeh, the Middle East's largest saltwater lake, has shrunk by half over the past two decades due to drought and dam construction on the rivers that feed it.

The lake, situated between East and West Azerbaijan provinces in the northwest, could dry out in the next two to four years and lead to apocalyptic consequences if no urgent action is taken, local officials and environmental experts warn.

The ecological disaster has led residents to organise demonstrations against what they deem as the government's inaction to save the lake -- a major source of income for the area.

Gatherings in the cities of Orumiyeh and Tabriz last week turned violent, according to official and opposition websites, prompting police to confront the protesters and make an unknown number of arrests.

Mohammadi-Zadeh said on Sunday that the government was ready to finance a plan which envisages "resolving the lake's problems in a five-year project."

He added that nearly 900 million dollars had been allocated to revive the lake with water from the River Arax -- which runs along Iran's borders with Armenia and Azerbaijan some 70 kilometres (45 miles) to the north -- as well as springs that feed the River Zab in neighbouring Iraq.

The vice president's remarks came despite parliament's earlier refusal to fast-track a rescue plan put forward by local lawmakers to save the lake.

The disappearance of Lake Orumiyeh would leave behind 10 billion tonnes of salt and could lead to the displacement of 14 million people, Orumiyeh member of parliament Javad Jahangirzadeh warned on Friday.