The Latvian Journalists' Association (LZA) was among those voicing continued outrage at the jailing of Greste and his Al Jazeera colleagues Mohamed Fahmy and Baher Mohamed after a trial on charges of aiding terrorism that all neutral observers judged to be a travesty of justice.
In a statement, the LZA said Greste - who has dual Latvian and Australian citizenship - had done nothing wrong and should be released immediately.
"Peter Greste has been falsely accused and convicted. He has done only his journalistic work without violating the principles of professional ethics," LZA chairperson Anda Rožukalne said.
Supporters of Greste and his colleagues are awaiting the results of an appeal to Egypt's discredited legal system, due to be delivered on January 1.
That could result in charges being dropped, a retrial or the upholding of his current seven-year sentence.
The UK's Guardian newspaper on Monday quoted Australian Prime Minister Julie Bishop saying she was "mildly optimistic" about the possibility of seeing Greste walk free in the near future.
Latvia has been actively working for Greste's release in concert with Australia and on Monday Foreign Minister Edgars Rinkevics vowed to carry on the fight:
A year ago #PeterGreste and his colleagues were arrested in Egypt, we'll continue to work tirelessly to make 2015 the year of their freedom— Edgars Rinkēvičs (@edgarsrinkevics) December 29, 2014