She was undergoing treatment at the Zoram Medical College (ZMC) near Aizawl when she died.
"It is with deep sorrow that I announce the demise of my beloved elder sister Lalvuani (88-years) this morning at 11:30 am," the Zoramthanga tweeted.
As per reports, Lalvuani was bed-ridden for months due to asthma and other age-relation ailments.
On September 22, she tested positive for COVID-19 and was shifted to ZMC.
Mizoram currently has the highest infection rate among all the northeastern states. On Monday, the state reported 527 new cases of COVID-19, pushing the state's tally to 88,693.
Meanwhile, the death toll rose to 295 as three more people succumbed to the infection.
The positivity rate was 31.77 per cent as the fresh cases were detected after testing 1,659 sample tests.
Moreover, at least 131 children were among the newly-infected people.
Mizoram now has 15,485 active cases.