Scotland's First Minister Nicola Sturgeon has announced she will resign after eight years in the job.

Ms Sturgeon said she will remain in office until her successor is chosen, but did not put a time frame on that election.

"This decision comes from a deeper and longer term assessment," Ms Sturgeon said, adding she had been wrestling with the decision for weeks.

"Giving absolutely everything of yourself to this job is the only way to do it.

"I leave the SNP free to chose the path it believes is the right one, without worrying about the implications for me and my leadership."

Ms Sturgeon became the leader of the ruling Scottish National Party (SNP) in the wake of its 2014 independence referendum, when the country voted to remain as part of the United Kingdom.

She was Scotland's first female first minister and the first woman to lead any of the UK's devolved administrations. 

Ms Sturgeon's outgoing remarks echo those of New Zealand's former prime minister, Jacinda Ardern, who also spoke of knowing when to vacate her post.

Ms Sturgeon turns 53 this year and said she wanted more out of life than simply politics. 

"Does that sound selfish? I hope it doesn't."

The outgoing first minister had recently become embroiled in a row over transgender policies after Scotland passed a Gender Recognition Reform Bill — making it easier for people to change their legal gender — however she assured the press conference that her resignation is not "a reaction to short-term pressures".

Tributes pour in despite divisions 

Tributes have been paid to Ms Sturgeon from across the political divide.

British Prime Minister Rishi Sunak thanked Ms Sturgeon her for her "long-standing service" and wished her all the best for her next steps.

"We will continue to work closely with the scotgov on our joint efforts to deliver for people across Scotland," he tweeted.

Scottish Labor Leader Anas Sawar admitted that they had "disagreed passionately about what is best for our people".

But he acknowledged that Ms Sturgeon had led the country through some of the "most challenging" times in recent history.

"Regardless of our differences, she is an able politician who has stood at the forefront of Scottish politics for more than 20 years," Mr Sawar said in a statement.

Former British prime minister Theresa May also pointed out they had their differences but thanked Ms Sturgeon for her service to the UK.

"We disagree on many issues but I'd like to thank you Nicola Sturgeon for your long, tireless service to our country & for the professional relationship we maintained as leaders," Ms May tweeted.

Scottish independence ambitions remain

Ms Sturgeon said she is not leaving politics entirely and will continue with personal campaigns, such as Scottish independence from Britain.

The SNP Party is currently embroiled in a debate over a second referendum on independence after the 2014 bid was narrowly voted down by the public.

The UK government has thus far refused to allow a second referendum, however Ms Sturgeon spent her tenure championing a continuation of efforts.

"The cause of independence is so much bigger than any one individual,” Ms Sturgeon said.

Ms Sturgeon did not offer specifics on the topic of her successor, defaulting to her party to set a timetable for one to be chosen, and refused to indicate who she would back as her replacement.

ABC/ Reuters