The line will be open from 9am to 5pm on Monday to Friday and aims to help cases go through before 30 June.
NatWest assured advisers that it had additional underwriting capacity enabling it to issue an offer within two days as long as cases were packaged with all necessary documentation and there were no delays in valuers accessing a property.
The bank vowed to instruct valuations on the first day for cases under £500,000 and within two days for cases over £500,000.
It also said it would accept search indemnity insurance to ensure deadlines were met.
Additionally, NatWest said it would extend offers for clients who were facing delays with their transactions.
For cases where a customer is one month away from the expiry of the offer, this can be extended by up to three months. For loans on new-build properties, offers can be extended for up to six months in three-month increments.
Brokers will need to have their client’s middle name, date of birth, address and postcode, loan amount or balance and bank details to hand when calling the support line.
Rate reductions and added cashback
NatWest has also reduced rates on new business products up to 90 per cent loan to value (LTV) and added cashback up to £250 on select mortgages.
Effective from tomorrow, two-year fixed purchase products with a £995 fee have been reduced by 0.01 per cent. Both products at 70 and 75 per cent LTV now have rates of 1.44 per cent, while the 80 per cent LTV mortgage has a rate of 2.54 per cent.
Elsewhere, a five-year fixed mortgage at 90 per cent LTV has seen a rate cut from 3.60 per cent to 3.55 per cent.
Five-year fixed remortgages have reduced by one basis point starting at 1.29 per cent for a 60 per cent LTV product at 2.69 per cent for an 85 per cent LTV mortgage.
Cashback has been added to the two-year fixed purchase product at 90 per cent LTV, which now offers a £250 incentive. This product has also had a rate cut of one basis point to 3.18 per cent.
The two-year fixed purchase mortgage with a fee of £995 now also offers £250 cashback. For five-year fixes, the cashback on the 85 per cent LTV product is now £150 while the 90 per cent LTV deal offers £250.
Elsewhere, buy-to-let product rates have been cut by as much as 0.13 per cent and green mortgages have been reduced by up to five basis points.