The new cuts see the pair offer rates of 1.49%, 1.99% and 2.49% for their two, three and five year terms respectively, with a product fee of £1495.
Lloyd Cochrane, head of mortgages at RBS and NatWest, said: “I’m delighted to be able to offer lower rates to customers and some of our best ever rates on lower loan to value mortgages.
“We want to continue with strong growth in our mortgage lending to homebuyers in 2015, helping as many customers as possible to buy their home as we play our role in the recovery and the future growth of the UK”.
Additional cuts saw the bank’s 90% 5-year fixed rate product fall from 5.33% to 4.39%, with no fee.
Their first-time buyer product, 90% five year fixed rate, also saw a sharp drop decreasing from 5.23% to 4.35%, with no fee.
Rates have been decreased on Help to Buy and other government scheme products by as much as 0.20%.
RBS and NatWest’s gross new mortgage lending to customers in Q3 2014 was £15.1bn. In Q3 mortgage lending stock grew almost to £103bn.