(ISTANBUL-AFP) - Turkey is planning to build a bridge across the famed Dardanelles strait to help ease traffic congestion in Istanbul, a minister said, revealing the latest in a string of mega projects under President Recep Tayyip Erdogan.

The straits, which separate Europe and Asia, were last bridged by Xerxes the Great, the Persian "king of kings" in 480 BC on his way to defeat the Greeks at Thermopylae.

"We are planning to construct a new bridge across the Dardanelles strait," Transport Minister Lutfi Elvan said in an interview with Turkish television late Thursday.

The Dardanelles lead into the Sea of Marmara which then goes into the Bosphorus in Istanbul itself. The waterway is one of the world's busiest shipping lanes, and is 1.2 kilometres (0.75 miles) wide at its narrowest point.

So far the Dardanelles strait can only be crossed by ferry.

"We will turn the entire Marmara region into a ring road, so this ring system will ease the Istanbul traffic to a great extent," Elvan added.

The Dardanelles, which played a key role in the great sea battles of ancient history, were also the site of one of the most famous battles of World War I when Ottoman troops resisted an invading Allied force.

It was also where the founder of modern Turkey Mustafa Kemal, the man who would later become known as Ataturk, made his name as a heroic military leader.

'Wildly excessive'

Turkey's Islamic-rooted government is under fire for its ambitious construction projects for the mega city of 16 million people, which critics have condemned as wildly excessive and damaging to the environment.

The projects include a massive new Istanbul airport, a third road bridge across the Bosphorus, and a canal parallel to the waterway to ease the permanent bottleneck of tankers and freighters waiting to pass through it.

Elvan said the government was keen on the third airport project, which is expected to cost over 10 billion euros ($12.5 billion), but declined to provide an exact time for the start of construction.

The gigantic new hub could be named after Erdogan, he said in August.

Erdogan, who once served as mayor of his home city of Istanbul, has proudly dubbed the pharaonic Canal Istanbul a "crazy project", boasting it could not even be compared to the Panama or Suez canals.

Feasibility studies are still continuing for the project -- which will be between 45 and 50 kilometres (28 to 31 miles) long -- aimed at reducing shipping traffic in the Bosphorus, which has been the scene of several accidents and oil spills, said the minister.

Turkish space agency

Nor is the sky any longer the limit for the government's ambitions, with Turkey also working to create a homegrown space industry overseen by its own space agency, Elvan said.

"With the creation of a space agency, we will very rapidly activate the activities in this sphere," he said.

The president has said the projects are needed to create a fast-developing and prosperous "new Turkey" that will be one of the world's top 10 economies by 2023.

The building industry has boomed in recent years, but while Erdogan was prime minister his government was shaken by a now-stalled corruption probe into allegations of high-level bribery linked to some construction projects.

Elvan vowed that the government would move ahead with mega projects, saying the government was planning a 17 billion Turkish lira ($7.6 billion/6 billion euros) investment in Istanbul.

Among the new projects is a direct metro line from Kadikoy to the Sabiha Gokcen airport on the Asian side of Istanbul, he added.

Last year amid great fanfare the government opened the first ever undersea metro link beneath the Bosphorus connecting the European and Asian sides of Istanbul.

This year it opened the first high-speed train link between Istanbul and the capital Ankara.