The body representing mortgage brokers has called on lenders to give approved borrowers eight weeks to proceed to drawdown at their agreed rate.
The Association of Irish Mortgage Advisors (AIMA) said in a rising rate environment, applicants are unable to meet the tight deadlines being set by lenders before the higher rate kicks in.
The association warned that the deadlines can result in the loss of deposits and house sales falling through.
Trevor Grant, Chairperson of the AIMA explained what they believe is a "perilous situation" faced by these mortgage seekers.
"Moves by lenders of late to introduce rate increases are expected and understandable - but what is not expected are very narrow timeframes offered to consumers who are in the throes of the property purchase process and mortgage switching, to avail of the lower rates - which were originally offered," he said.
"This situation could potentially be disastrous for the people affected.
"Mortgages invariably take months from first application to closing. However, thousands of people who are well advanced in the process are now being asked to close within a very short timeframe that is for most simply not possible," he added.
He pointed out that many applicants will have signed contracts and paid potentially non-refundable deposits to purchase their new home.
"Equally, a number of those approved may not have sufficient time to organise alternative and more appropriately priced mortgages," he added.