The Bush and Mid Antrim 150 road races have not been included in the events calendar listed by the Motor Cycle Union of Ireland for the 2015 season.
The Bush races were called off in 2013 because of rising insurance costs and the organisers' difficulties in finding the necessary sponsorship.
The event returned in 2014 but will not be staged this year.
The Mid Antrim did not take place last year for financial reasons and looks set to be absent again this season.
The Bush race organisers have been unable to gain the support needed to make the meeting a viable proposition for 2015, although they plan a return next year.
With that in mind, a meeting of interested parties who wish to see the event back in business in 2016 will take place this Saturday, 31 January.
Ballyclare rider Jamie Hamilton secured a four-timer at the Bush races in June.
The only three national road races set to take place in Northern Ireland in 2015 are the Cookstown 100 in April, the Tandragee 100 in May and the Armoy races in July.