A Christchurch City Missioner's remaining positive a social housing project will still go ahead.

That's after plans to convert the old City Mission building into an emergency refuge now costing $250,000 more than expected.

The Christchurch City Council's contemplating using the Mayoral Earthquake Relief Fund to cover the shortfall.

City Missioner Michael Gorman says fire compliance issues have hiked up costs.

"The council really aren't the problem. They're are working very hard with us. It's always a bit of an unknown but I'm very hopeful it will. It's a very small project but will help families over a long time."