The first minister said people from every single part of Wales have been affected by the scandal – which was recently the subject of an ITV drama, Mr Bates vs the Post Office.
More than 700 sub-postmasters were wrongly convicted of fraud, theft or false accounting between 1999 and 2015 based on information from accounting software called Horizon.
At first minister’s questions on Tuesday, January 16, Clwyd South MS Ken Skates said compensation and quashed convictions are long overdue.
Mark Drakeford agreed with the Labour backbencher, urging the UK Government to act now.
He said: “Many people will ask where they have been all these years.
“But now they need to act, they need to make sure that those people are properly identified and that compensation for the wrongs inflicted on them is paid to them as fast as possible.”
Delyth Jewell raised concerns about Transport for Wales awarding Fujitsu – a Japanese company which developed Horizon – a five-year contract in 2019.
The South Wales East MS said the contract has since been extended to April 2026, and urged the Welsh Government to review contracts with Fujitsu, suggesting the company should be blacklisted from getting any future contracts if it is found guilty of deliberate corporate abuse.
Mr Drakeford said two contracts will be reviewed naturally as they come to an end, and described blacklisting Fujitsu as a legally questionable course of action which would have to be weighed up carefully.
Describing the scandal as the largest miscarriage of justice in UK history, Mark Isherwood said 17 UK ministers have been responsible for the Post Office in that time.
He suggested a Labour UK minister rebuffed calls to investigate malpractice in 2009.
The Conservative, who represents North Wales, pointed out that the UK Government has brought forward a bill to ensure all victims of the scandal receive compensation.
Mr Drakeford argued the UK Government has not attached sufficient priority to the issue.
He raised the example of a letter from Welsh ministers to the UK justice secretary going unanswered for more than six months.