Bank Confident IT Problems Almost Over
The RBS Group says the IT chaos affecting customers of its banks NatWest, RBS and Ulster should be over by Monday.
The problems - caused by an issue with computer software - have affected millions of users across the UK.
A total of 1,200 NatWest branches opened on Sunday for the first time ever, as the bank attempted to clear a huge backlog of payments caused by the glitch.
But Susan Allen, from the RBS Group, has told Sky News the technical crisis is almost over.
"I can confirm that we are making progress to clear the backlog of payments and I'm cautiously optimistic that RBS and NatWest customer account balances will be largely back to normal from tomorrow (Monday)," she said.
"The knock-on effects of this technical failure mean there will bumps in the road. We will do everything we can to minimise further disruption to our customers."
Ms Allen said RBS will ensure the glitch does not cost customers any money.
"We will automatically waive any overdraft fees or charges on current accounts. This will be processed over the next few days," she said.
"We will work directly with credit agencies to ensure no one has their credit score affected.
"For all other issues, customers have our commitment that they will not be out of pocket from this issue. We will publish further details on how we will ensure this later in the week."
Around 7,000 staff were on duty in branches on Sunday, but social media sites such as Twitter continued to be flooded with angry messages from customers who found themselves without access to cash over the weekend or unable to pay bills.
One wrote: "My bills are still coming out but my wages have not gone through. Can't afford food or fuel to get to work on Monday."
Another tweeted: "3 days and still no wages. Won't be able get into work tomorrow night due to lack of funds. Zero cash can't pay bills, buy food ect."
And customers who had previously been able to view their balances - albeit out of date - earlier told Sky News that they could not access the website at all for a period.
RBS said it was still experiencing technical issues which meant some account balances may not be showing correctly, while it also admitted some online services were unavailable.
Stephen Hester, chief executive of NatWest owner RBS, has issued a public apology for the technical hitch and admitted the bank had let down its customers.
Branches opened their doors between 9am and noon, amid continued anger following days of disruption.
The chaos left many of its clients unable to pay bills or access their money.
Mr Hester strived to reassure customers following fears thousands of people could be hit with penalty charges if their regular payments - including mortgages - were affected.
"I am very sorry for the difficulties people are experiencing," he said.
"Our customers rely on us day in and day out to get things right, and on this occasion we have let them down. This should not have happened.
"Right now my top priority, and the priority of the entire RBS Group, is to fix these problems and put things right for our customers.
"This is taking time, but I want to reassure people that we are working around the clock to resolve these problems as quickly as we are able."
NatWest has more than 7.5 million personal banking customers but it is unclear how many have been affected.
Ulster Bank said about 100,000 of its customers experienced difficulties. While the original technical glitch has been fixed, staff are now working through the build-up of transactions which have not been processed.