The brand, owned by PepsiCo, will invest £4m in the launch next year. The activity will include TV ads created by Abbott Mead Vickers BBDO.
The launch marketing will appeal to consumers seeking healthy snack options following the excesses of Christmas and the New Year.
Both the Mini Bagels and Mini Breadsticks packs will contain less than 10% fat. They will target consumers who want an alternative to Snack-a-Jacks' rice cakes.
To distinguish the lines from the core products, design agency Vibrant has created packaging that displays the bagel and bread-stick snacks, giving them 'handbag appeal' and a fun positioning.
The packs will be available in major multiples from January.
The expansion marks the latest salvo in a war between the snack brands that has seen Snack-a-Jacks dominate the market.
In September, rival Jacob's cut back the number of products in its Thai Bites range, worth £7.5m in 2004, in the face of fierce competition.
The rise in popularity of rice-based snacks has been matched by increased marketing investment. Snack-a-Jacks gave its main brand and Mini Bites offerings a combined advertising budget of more than £3m in 2004, according to Nielsen Media Research.
The brand's rice snacks captured an estimated 16% of the UK non-sweet biscuits market, worth a total of £285m, this year, according to Mintel - double that of nearest rival Jacob's Cracker Collection. Own-label snacks accounted for 43% of sales.