UK finance minister Rachel Reeves says she plans to cut the costs of running the government by 15 percent within four years, as she grapples with strained public finances.

Her comments came ahead of her crucial Spring Statement on Wednesday when she is expected to detail billions of pounds of spending cuts across various government departments.

Reeves said it would be up to individual departments to decide how many civil servants will lose their jobs but added that personnel could be cut by 10,000.

Reeves also insisted that she will stick to her own fiscal rules when she delivers her financial update on Wednesday.

They are not to borrow to fund day-to-day spending and to see debt fall as a share of the gross domestic product by 2029-2030.