Danish Prime Minister Anders Fogh Rasmussen's departure to take over as Nato chief will leave behind a political void in the Scandinavian country, according to observers.

Rasmussen, who has headed up a centre-right coalition government since 2001, was appointed the next Nato secretary general yesterday despite initial opposition from Turkey.

His expected resignation as prime minister will "undoubtedly (leave) a huge political void" in Denmark, Thomas Larsen, a political commentator at the Berlingske Tidende daily newspaper, told AFP.

"There has rarely been a Danish leader who has so completely dominated the political scene as Anders Fogh (Rasmussen), by pushing through his strategy and holding an iron grip on his centre-right coalition," he said.

While Rasmussen long refused to confirm his Nato candidacy, he appears to have been laying the groundwork for the next Danish administration for some time, preparing for Finance Minister Lars Loekke Rasmussen - no relation - to take over his job.

The heir-apparent would likely "pursue the same domestic and foreign policy" as his predecessor, but Rasmussen's departure would nonetheless mark "the end of an era," Larsen said. Renowned as a skilled tactician, the prime minister has won three elections in a row - a first for his Liberal Party.

He has, however, acknowledged he owes much of his success to what many would describe as an unsavoury alliance with the far-right Danish People's Party (DPP).