Norway's decision to allow a jihadi bride to return from Syria with her two children could lead to the collapse of the country's coalition government.

Prime Minister Erna Solberg came in for immediate criticism after agreeing to the repatriation of the 29-year-old woman so her seriously ill five-year-old son could receive medical treatment.

But the decision caused a rift in the coalition between her Conservatives and the populist anti-immigration Progress Party who say the woman poses a security risk due to her links with Islamic State.

One Progress MP accused her of 'negotiating with a terrorist'.

Prime Minister Erna Solberg (right) has come under fire from her coalition partner Siv Jensen (left), the leader of the anti-immigration Progress Party

The 29-year-old jihidi bride will be arrested when she returns from Syria and her children will be given a temporary new guardian (file photo)

Opposition deputy leader Hadia Tajik jumped on the remarks, saying that such a major disagreement is untenable between members of the same government.

'This issue shows, first and foremost, that Erna Solberg will truly swallow camels with backwards hair to stay in government,' Tajik told NRK.

Progress Party leader Siv Jensen is now set to issue a set of demands to the prime minister in order to keep the shaky coalition intact, saying that her populist party was not prepared to remain in government 'at all costs'.

She said: 'It will then be up to Erna and the Conservatives to take it seriously or not. This must happen quickly, because the cup is now full.'

She said earlier: 'This comes in light of us long being denied support over our key issues, and we're not in government for this.

'We think the Conservatives are being far too accommodating to the Liberals and Christian Democrats.

'That results in an overall grey and boring politics.'

Withdrawal from government by the Progress Party could potentially result in Solberg being forced to call an early general election.

If Solberg continued as head of a minority government, she would still need the support of the Progress Party to pass legislation.

Reports earlier in the week suggested that regional Progress Party leaders are already set on leaving the coalition.

Dagfinn Henrik Olsen, leader of the party's Nordland county branch, said: 'It's high time we left before the last of what we know as the Progress Party is gone. What is happening now is simply embarrassing.

It's hard for us genuine party members to see.'

On social media, Progress Party MP Roy Steffensen accused the government of 'negotiating with a terrorist'.

'The terrorist won,' Steffensen tweeted.

The 29-year-old mother will be arrested on arrival in Norway, NRK has reported.

That means a temporary guardian would be assigned to her two children, aged five and three, the broadcaster writes.

Meanwhile pressure on Jensen to make a drastic stand over the issue appears to be growing.

With the Progress Party scheduled to meet again to discuss its strategy at the end of the month, Solberg is likely to have to take steps within the next two weeks to placate her erstwhile closest parliamentary ally.