Treviso and Zebre might be forced to leave the Pro12 according to reports which claim they owe €1.5m to the league.
The Italian sides apparently have until the end of May to pay the money or face expulsion according to a BBC report.
London Welsh and London Scottish have been sounded out as possible replacements if the Italians were to leave, with Scottish chairman Sir David Reid admitting his club would be open-minded about a switch to the Pro12.
Any such change would still require the agreement of the RFU, with the Exile clubs affiliated to both the RFU and the WRU and SRU respectively.
The Italian clubs had threatened to pull out of the Pro12 last season, with Treviso losing a host of players over the off-season as a result.