Mark Drakeford has said the Welsh government was willing to talk to rugby bosses after he was urged to throw the game a financial lifeline.
The Welsh Rugby Union (WRU) is asking for "breathing space" to help repay an £18m Covid loan to Welsh ministers.
The first minister told the Tory Senedd leader his government would look at what could be done but the WRU had borrowed money on commercial terms.
Andrew RT Davies had asked whether the loan could be restructured.
At question time in the Welsh Parliament, Mr Davies said that the government should make sure that "there isn't that burden placed on the grassroots game within Wales, should the WRU have to make cutbacks", he said.
Mr Drakeford said the Welsh government had "stepped in as the lender of last resort" when the WRU "weren't able to sustain" payments on an earlier Covid loan.
"When you are dealing with public money, even when you are dealing with organisations that are as important in Welsh life as Welsh rugby is, you still have to make sure that those loans are being made on properly commercial terms," he said.
He added: "While we are always prepared, and have been prepared, to talk to the union about whether the loan can be restructured - whether there are other ways we can assist - in the end this was a commercially-determined loan, conditions inherited from the UK coronavirus assistance and entered into freely by the WRU itself."
Such a loan would not be available from a bank "so they are already at an advantage in that way, but that doesn't mean we are not willing to talk to them and see if there's anything else that can be done".
It follows an appearance by rugby bosses at the Senedd's Culture and Sport Committee last week.
Senedd members were told the interest rate on the loan's repayments had risen to 8.5%.
WRU chief executive Richard Collier-Keywood said the repayments cost £2m a year and were having a "very severe" effect on the four professional sides: Ospreys, Cardiff, Scarlets and Dragons.
"If we do not get that breathing space we are going to a Plan B as yet undefined," he said.
