The system will be closed from 5pm today until 8am on Monday, subject to all maintenance work being conducted successfully.
A spokeswoman for Barclays says: “This means that brokers will not be able to book cases over the weekend but they will still be able to submit and package any cases they have booked with us over the last five days.
“We apologise for any inconvenience this may cause.”
Last week Barclays reduced its funding tranches in an attempt to control demand, leaving many brokers unable to book funds.
The restrictions have not yet been lifted and earlier this week the lender increased rates on some of its fixed rate mortgages in a further effort to manage levels of business.