Finnish media claimed centrist Prime Minister Juha Sipila pressured public broadcaster Yle to stop investigating the alleged conflict of interest after a company owned by his family won a major order from a nationalised mine.

But Sipila denied any intention of doing so.

"I admit that it's a soft spot when my position affects my family and my family gets involved... I admit to having reacted emotionally," he told reporters.

The case centres on an order received by Katera Steel -- an engineering company owned by Sipila's family -- from a nickel mine that had received a cash bailout from the state.

On November 11, the government announced it would invest 100 million euros ($107 million) in Terrafame, the company operating the unprofitable mine that would have shut down without the intervention.

Sipila allegedly contacted the editor of Yle, Atte Jaaskelainen and sent nearly 20 messages in one evening to a journalist investigating the matter.

The premier had reached out following the publication of Yle's first piece on the issue in a bid to discourage further coverage, according to the weekly news magazine Suomen Kuvalehti.

Though Sipila was given a chance to comment on the story hours before publication, he complained on Wednesday that was not sufficient.

"I have not shut anyone's mouth... The piece of news contained a serious allegation about favouring relatives, which was not the case. A possibility to comment should have been given," he said.

Denies wrongdoing

But Suomen Kuvalehti reported that the pressure allegedly led Yle to scale down its coverage of the story.

It also revealed that Yle's management had threatened to fire one of its most renowned journalists who planned to discuss the topic in his weekly talk show.

Jaaskelainen denied bowing to pressure from the prime minister.

"My reasoning is that there was no reason to proceed with the matter... We took this decision ourselves on journalistic grounds," he wrote on Yle's website.

Sipila has denied any wrongdoing in the transaction.

Katera Steel's deal with the mine "had been confirmed before the (state funding) decision," Sipila said.

Antti Rinne, chairman of the biggest opposition party the Social Democrats, said the claims about Sipila interfering with the public broadcaster's work were "very serious".

"Finland is a leading country in press freedom. If the claims about Sipila hold true, we will be facing a serious crisis," Rinne wrote on Twitter.

Production at the Talvivaara mine about 500 kilometres (310 miles) north of Helsinki began in 2008 and was one of the largest nickel mines in Finland. It was nationalised in 2014 to avoid closure.

It caused one of the worst environmental disasters in the country's history when, in 2012, a leak led to nickel, cadmium, uranium and zinc seeping into surrounding rivers and lakes.