The sentences appeared to be the most severe for any of the dozens of members of Ms Suu Kyi’s National League for Democracy, who were arrested after the military seized power on February 1.
Former Kayin state planning minister Than Naing was convicted by the state court of six corruption charges and given a 90-year prison term, including labour, lawyer Zaw Min Hlaing said.
Nan Khin Htwe Myin, 67, the former chief minister of Kayin state and a senior member of Ms Suu Kyi's political party, was sentenced to 15 years in prison on each of five charges.
Ms Suu Kyi is also being tried on corruption and other criminal charges that her supporters say were concocted to discredit her and legitimise the military’s seizure of power.
Any conviction would probably prevent her from running in elections that the military-installed government has promised to hold by 2023.
Nan Khin Htwe Myin, a member of the party’s Central Executive Committee, is a veteran pro-democracy activist who was first arrested in 1974 during a student protest under a previous military government.
She was arrested at least two more times before she won election to the state parliament in 2012 and 2015, after which she was appointed state minister. She is known for being a close colleague of Ms Suu Kyi.
She was detained by soldiers on February 2 and placed under house arrest, where she made a live-streamed broadcast calling for civil disobedience against the army takeover. She was then arrested on February 8.
Myanmar has been mired in violence and civil unrest since the military seized power. Protesters against the takeover – who faced beatings, shootings and arrests – have turned increasingly to armed resistance.
Insurgents are active in many parts of the country.
One of Nan Khin Htwe Myin's corruption charges involved alleged misappropriation of state funds for medical treatment after she was injured in a car accident in 2017.
In four other cases, she and Than Naing were accused of malfeasance and mishandling funds.
Both had already been convicted of inciting unrest after the army takeover and sentenced to two years in jail.
Nang Khin Htwe Myin is in good health at a prison in Hpa-an, the capital of Kayin state, but has lost some weight, her lawyer said.
“The chief minister sent the message to the people to always to be united, to try together to bring forth a democratic federal union and to participate together in overcoming the evils of the military,” the lawyer said.