The Hepworth Wakefield, a £30m art gallery being built next to the River Calder on the edge of Wakefield city centre, has seen several proposed opening dates come and go.

In 2005 Wakefield Council said it was "expected" to open in 2008 and a year later the authority said it would open by March this year. In 2007 the council predicted an opening date of winter 2009/10 and in 2008 the authority said it was "due to open in 2010".

But the council now says it won't be open until spring 2011 and gallery bosses say it will be several months before they can name a day for the grand opening.

The Hepworth's director, Simon Wallis, yesterday gave the Yorkshire Post a tour of the two-storey building, which boasts 10 galleries and has about 60 construction workers on site six days a week.

He said it took time to arrange long-term loans of major pieces from galleries including the Tate.

"The bottom line is that we want this building open as quickly as possible. I want to make sure that when we open it is world class."

Mr Wallis said it also took time to recruit the 40 staff needed to run the gallery, which will include a café, 100-seat auditorium and an educational facility for children.

He believes the Hepworth, designed by acclaimed architect David Chipperfield and named after Wakefield-born sculptor Dame Barbara Hepworth, will attract upwards of 200,000 visitors a year.

"It will be the third largest gallery outside London, after the Baltic in Gateshead and the Tate Liverpool. We expect more than 200,000 visitors in the first year.

"We want to get Wakefield into the national consciousness as a visitor destination."