Billionaire former Georgian Prime Minister Bidzina Ivanishvili insisted in a farewell letter Thursday that he will use his influence to ensure the ex-Soviet state remains pro-Western, while denying he plans to rule from the shadows.

Ivanishvili -- the Caucasus nation's richest man -- made good on a pledge to step down after a year in charge when his hand-picked successor Irakli Garibashvili,31, took over on Wednesday.

In a five-page open letter entitled "Post Scriptum", Ivanishvili promised to keep pushing for Georgia to stay committed to its aim of joining the EU and NATO while also continuing attempts to soothe ties with Russia left shattered by a brief 2008 war.

"Human rights, European values, Euro-Atlantic aspirations, the fact that America should be our strategic partner; the fact that we must reset relations with our neighbours, including Russia: these are the values I cherish," the enigmatic tycoon wrote.

"If someone is against it, yes, he or she should be concerned, as I will surely exercise influence in this direction."

Georgia is set to initial a key free trade agreement with the EU at a summit in Vilnius later this month and the new government has pledged to stick to Ivanishvili's foreign policy priorities.

While he admitted that with his close allies in power he will retain considerable influence, Ivanishvili, 57, said he would feel free to criticise the authorities but would not seek to control the government.

"I never govern behind the scenes. I would never insult my country and my team -- for whom I have a tremendous amount of respect -- by doing so," he wrote in the letter.

Ivanishvili-- who saw another loyalist Giorgi Margvelashvili cruise to victory at presidential polls last month-- has said he will move into civil society after stepping down but did not give any more specific details on his plans.

The yoga-loving magnate-- who owns a private zoo and priceless modern art collection-- emerged from seclusion a few years back to wrest power from his arch-foe former President Mikheil Saakashvili who he accused of authoritarianism.

In his valedictory epistle Ivanishvili said that despite his "excessive wealth" his "heart and soul" had only been set on "being a free citizen of one's free homeland".

"Fulfilling this dream was the reason behind my coming into politics and my departure therefrom serves the same purpose," he concluded the letter.

"In reality, things are much simpler than they seem."