Costly, 43, has matured into New Zealand's best veteran, setting the veterans half marathon record in 2010. This year, he will have his eyes on Jack Foster's veteran record, which dates back to the first Christchurch Marathon in 1981.
There is no doubt that Costley is still good enough to win overall. He won Rotorua last year, and was third in the Christchurch half marathon in 2010 and second in the full marathon in 2011.
Warrander, whose personal best marathon came in 2004 in Japan, won't be lacking in motivation.
The 39-year-old has won every major marathon in New Zealand except Christchurch. A win there would crown his career and his second place last year was the only time Wreford has beaten him.
In 2011, Warrander won Rotorua and the Christchurch half marathons. In 2010 he beat Wreford to win the Auckland Marathon.
So while Wreford has recent form on his side, Warrander and Costley have run better times over all distances.
In the women's full marathon a strong field once again lines up for the signature race on Queen's Birthday Weekend.
Lisa Hunter-Galvin is looking to claim her third consecutive win at the Christchurch Marathon.
In 2011, the 44-year-old chose Christchurch as her first race after a drug suspension and silenced her critics with a win.
She backed that up last year with a win ahead of Wellington's Gabrielle O'Rourke, who she also beat at Rotorua last year.
Angela Leck from Wellington, who finished third last year, will challenge Hunter-Galvin and Dunedin's Victoria Beck will also be a contender.