The main opposition Social Democratic Party launched its election campaign more than a month ago, but the party's parliamentary group met for the first time this year with the party leader on Friday.
The parliamentary delegation held a coffee reception on Friday morning to welcome Antti Rinne back to work after an extended sick leave.
Rinne also appeared before a TV camera for the first time this year, interviewed briefly by a reporter for Yle's morning chat show, Aamu-tv.
Rinne, 56, fell ill with pneumonia while on holiday in Spain around Christmas. After returning to Finland on January 11, he was also diagnosed with a coronary thrombosis, which was treated with a balloon angioplasty. Rinne says that his condition was also worsened by a hospital-acquired infection.
Rinne aims for premiership
The SDP kicked off its election campaign in late January, led by deputy chair Sanna Marin, a first-term MP. The SDP says it aims to become the nation's biggest party and to make Rinne the next prime minister. The party has held firmly onto the number-one spot in Yle opinion polls since last summer.
Alongside an interview with the tabloid Ilta-Sanomat last week, Rinne released a physician's statement saying that he did not have any illness or injury that would "prevent him from continuing as a Member of Parliament or other corresponding work as of 1 March 2019”.
Also last week the former union boss said in a Facebook post that he felt “good and enthusiastic”.
IL: Seriousness concealed
On Thursday the tabloid Iltalehti reported that Rinne's condition had been much worse than reported by the party, saying that he had been in an induced coma for at least two weeks and was medevacked back to Finland in that condition.
The paper suggests that the party had deliberated tried to conceal the seriousness of his illness, suggesting that there was a power struggle behind the scenes, with some hoping to replace Rinne as the party's prime ministerial candidate.
Advance voting for the next Finnish Parliament begins on 3 April ahead of Election Day on 14 April, followed by the European Parliament election on 26 May.