Magufuli was declared the victor of October 28 election with 84 percent of the vote, but the opposition and diplomats have dismissed the process as a sham.
In the wake of the vote, leading opposition members, including main presidential candidate Tundu Lissu, were among around 150 arrested.
Lissu eventually sought refuge at the German embassy before returning on Wednesday to Belgium, where he had previously received medical treatment after being shot 16 times in a 2017 assassination attempt.
Planned protests against the election result were quickly quashed with a string of arrests and heavy police presence.
“The purpose of freedom and democracy is to bring about development, not chaos,” Magufuli said Friday, inaugurating the new parliament dominated by the ruling Chama Cha Mapinduzi (CCM) party.
“Freedom, rights and democracy go with responsibility and each has limits. I hope I’m well understood.”
Magufuli laid out his priorities, such as infrastructure including the building of a key railway and a controversial hydropower plant in the Selous Game Reserve.
He also said wants to accelerate economic growth — which stood at a pre-Covid-19 average of about six percent — to an average eight percent annually over the next five years.
Aside from a landslide win in the presidential race, the CCM took 97 percent of the 264 seats in parliament, with the most popular opposition MPs losing their seats.
Aside from Lissu, who said he was leaving both for medical reasons and over concerns for his security, another leading former opposition MP Godbless Lema sought refuge in Kenya.