Small field sizes in National Hunt racing is "arguably the biggest challenge facing racing, and in particular jump racing", according to British Horseracing Authority chief executive Paul Bittar.

Bittar's comments come in the wake of 14 of the 21 races last weekend having to be re-offered at the final declaration stage, while this Saturday's Grade One Long Walk Hurdle will have a maximum of just five runners if all the contenders stand their ground.

The issue of small field sizes was a priority for the BHA during the compilation of the 2015 Fixture List and race program.

"The British racing public's affinity for jump racing is clear and its popularity is undiminished," Bittar said.

"Attendances continue to be very strong for the feature meetings, as exemplified by the record crowds at this year's Cheltenham Open meeting, while eight of the top 10 betting races so far in 2014 have been jump races.

"However, we have made it very clear over the past months that arguably the biggest challenge facing racing, and in particular jump racing, is the issue of small-field races and the importance of competitiveness at all levels of the sport.

"This trend was predicted and is exactly why we have taken action to address it by introducing a range of robust measures, including the removal of around 100 jump races from the program in 2015.

"Small-field and uncompetitive races are damaging for British racing. They are unattractive for punters as a betting medium, they undermine the credibility of the sport internationally, and crucially - in a factor sometimes overlooked - they create much greater threat of integrity issues.